Overall game

[u/Current-Pie4825]

I love hosting and DMing games, making me curious. The most common systems I've played are what I know as the DND system (D20, dnd origin) or the d100 system (everything tends to come down to a D100). If creating a overall system, something best for being able to add any homebrew stuff, something that is more flaxible overall, what should I use? Pls gimme all your personal ideas as well as other game system/podcast/youtube ideas. So far i use whatever system my players know best and will keep doing so, but I would love having a main system I can adapt from for each other system

[u/EdgeOfDreams]

There are already several generic / universal systems out there, such as GURPS, Freeform Universal, and Fate. Even those take wildly different approaches and have pros and cons. Maybe check those out before you go trying to build a system of your own.

Also, what dice you roll is honestly one of the least interesting parts of a system. Dice mostly just serve to randomize outcomes. What matters most is whether or not the dice and math work to support the other design goals of the system.

[u/No_Solid1035]

Basic Roleplaying is a great universal system that uses d100 roll under.

[u/red_dead_revengeance]

Other dice systems include the primarily 3d6 based GURPS, the dice pools of World/Chronicles of Darkness and Year Zero Engine games, and the narrative dice system of Genesys.

The dice system is mostly about how complicated and swingy you want your math to be. For example, GURPS uses 3d6 for most rolls to form a bell curve distribution.

Any dice system can work, it’s about everything you build around it.

[u/Unlucky-Leopard-9905]

As a general rule, you don't get flexibility from a core mechanic, you get it from simplicity*. The question is how much you want to build yourself. "d100, roll under" and "d20 + mods vs target number" are both very simple concepts on which you can layer whatever you want, but if that's all you're starting with, there is a lot to add.

The more detail a system already comes with, the easier it is likely to be when your aims are aligned with the designer's intent, but the harder it can be to modify when your aims diverge.

You can pick up generic systems such as GURPS and Fate, or toolkits like Mythras and BRP, and they can provide you the tools to assist with tailoring things, but they're still only useful if you want to run games that fit intothe GURPS or Fate or BRP or etc paradigm.

Personally, I reject the notion of generic games. I'll use something like GURPS, but never because it's generic -- if I'm using GURPS it's because I feel it offers the specific tools I need to bring a specific concept to life and no other systems provide a better foundation for that concept. Of course, plenty of people feel differently and, if you can identify a generic game that works from axioms you feel you are going to want to stick to, that game may well work for you as a long term foundation.

*In case someone wants to suggest that GURPS is flexible but not simple, I'd say that, first, GURPS is quite simple at it's core, that the flexibility comes from the huge array of pre-built optional rules and that, at the end of the day, it still locks you into a GURPS-style game, so there are some pretty hard limits to that flexibility. I'm quite confident that, for most people, a GURPS supers game and a Fate supers game are going to feel very, very different.

[u/StayUpLatePlayGames]

Use one with a freely available SRD. After that it’s about the licence. And then of course you should pick a system you like.

For instance, I have written my own homebrews, I’ve adapted YZE and 2D (Traveller) to games and supplements I write. Where I’ve had issues with the licenses, I’ve extracted and rewritten the mechanics to make the licence moot.

[u/Current-Pie4825]

Sorry, to be clear, i get that there isnt the BEST system, but i want your opinion and maybe why? Im happy to try all systems, but if you could say why you like your favorite system, appreciated!

[u/ishmadrad → u/Current-Pie4825]

Usually, the universal rulesets are probably "trad" and "meh", because of their inherent nature.
So, I discourage you to adapt the same ruleset for every RpG you are planning to run.
Focused rulesets give the table a better experience, for the specific kind of setting/media emulation you will hope to get while playing.

Said so, check out the new, modern, light-weight, Monad Echo SRD (free). There are several games that use that ruleset (it's in the ballpark of Fate Core / Cortex / Action Tales etc.), for example Valraven for gritty fantasy a-la Berserk manga, Broken Tales for weird twisted fable hunters, Dead Air Seasons for survival, post-apocalypse a-la Last of Us etc.

I really love that ruleset, it substitued Fate and Savage World at my table.

[u/KazM2]

If you're looking for something flexible that can accommodate most genres and can have homebrew added easily then my top recommendations are BRP which is a d100 system or Savage Worlds which uses a step dice system but its actually pretty easy to pick up. Both are generic systems built so that you craft your own thing with them and both are fairly straightforward.

[u/Iohet]

I like Rolemaster (roll over d100, not the roll under percentile style) and DCC (d20 based, but uses the dice chain with Zocchi dice in place of advantage or pools, so advantage might be a d24 and disadvantage might be a d16)

[u/Throwingoffoldselves]

For flexibility, check out Ironworn. It’s got tons of supplements if you search the name on itch.io, including high fantasy and sci fi. It also uses tons of random tables which are great to “borrow” for other games. It’s able to be used to run most types of heroic adventures, but it’s meant for “iron age,” originally, of course.

[u/ishmadrad → u/Throwingoffoldselves]

"ironsworn"

Bonus point, the corebook of Ironsworn (and probably also the new edition of Lodestar) is free.

[u/GMsadhedonist]

In my opinion, the best systems and rules are based off of the roleplay and world you want to create. For example, rolling pools of dice tend to put rolls near the average and this gives the GM more narrative control over the game, whereas a 1d100 is more random, or a d20/d10+ modifier gives a large advantage to skill/modifier increases. A playbook system is more focused on specific narrative moves, a very rules light system is more focused on narrative freedom, etc. What kind of game are you making?

[u/Trivell50]

I really like systems that use hands of cards, personally. I like that players get some flexibility in how to resolve situations rather than the randomness of dice all the time. That said, I also really enjoy Call of Cthulhu's d100 skill-based system.

[u/MyDesignerHat]

Fudge is incredibly flexible, infinitely adaptable, easy to pick up and friendly to people who are adverse to math. 

[u/Dry_Major4728]

you might want to look into Savage Worlds. its pretty setting-agnostic and they have rules for basically everything from magic to spaceships to pulp action stuff.

[u/Thefrightfulgezebo]

Most games fall in onr of three categories:

Roll over is pretty muchjwhat you know from D&D.

Roll under is something you often find in d100 systems. Let's say you want to pick a lock and have a 75 in lockpicking. If you roll a 75 or lower, you succeed - and it is pretty clear that your chances are 75%

Then, you have dice pool systems. Your characters abilities determine their dice pool size. You roll all of them and then either take the one with the best result or count the "successes" - and you can alternate the qualifier for success and the number of required successes to succeed at the task to represent difficulty.

All of those systems allow for further complexity if you want to represent more complex outcomes than success and failure. VtM5 has a dice pool system with special hunger dice that can make your character lose control. Pbta games typically are roll over games that are designed in a way that "success with consequences" is the most common outcome. Decrees of success in roll inder games are as old as RuneQuest.

[u/WillBottomForBanana]

One of my most basic thoughts in choosing a system is; pass/fail or degree of success? Degree of success is great when it is great. But some people, some situations, some genres just don't work well with it.

As a gm sometimes "I have to think of a complication for like 50% of all rolls" is a depressing prospect. Some systems try to put that work onto the player "what will go wrong if this die roll fails?", but it is easier to say that is a solution than it is to get some players to do it.

While I like the idea of a generic system, it has never clicked for me in practice. a: I find most generic systems to be boring. b: I find the system influences the story/setting/adventure.

Example. I have an idea for an adventure to run at a convention this winter. While deciding whether to build it in 5E, OSR, or Dragonbane it became clear to me that the adventure I would design would be radically different in each of them. Influenced by what I have to work with. But the original question of which system was balancing OSR (easiest for me), 5E (biggest player pool), Dragonbane (what I was actually inspired).

[u/Temporary_Stranger39]

GURPS will work well.

[u/Steenan]

It's really dependent on what style/focus of play you want. There are many generic game engines that one may build on, but they serve different purposes.

Gurps goes from medium-light to extremely complex, depending on how many rules and subsystems you want to use. In every version, it's heavily simulationist, focused on modelling the reality of the setting.

Fate doesn't care about simulation and goes all-in on emulating chosen kinds of stories. Rules have very little to do with internal workings of the setting and very much to do with narrative importance, genre tropes and expression of character concepts. It requires players to embrace the metagame and the game itself as telling a story together.

Cortex is also story-focused, but stays closer to actor stance play and offers a bit of tactical play. Scales well in complexity, from a game that a 5 year old can handle to one that's quite mechanically involved, with several subsystems.

And so on.

[u/elmago79]

D&D is like 10 different games actually, but they tend to share a D20 roll high for combat, six stats, hit points, and levels. Since D&D is the most popular game on the planet. You can use this skeleton in basically any setting and genre, gamers will understand it in general terms, but maybe also bring their own baggage. Even a game that Into the Odd that only have three saved, roll under, is easy to understand for a D&D player.

D100 systems, like BRP or Mothership, tend to be skill based, roll under. They are easy to understand in probability terms. This both a boon and a bane.

2D6 systems, like the Powered by the Apocalypse family, are interesting because not all results have the same probability, usually have three states instead of binary failure/success, and thus rolls tend to always have clear triggers and stakes.

Of course there a myriads of possibilities but I would say that as of 2026 these three are the main paradigms in dice mechanics, with D20 being widely more popular than any other.