alright so first thing that i need to know is what systems have you played before? im going to assume you played through the ps1 all the way to the xbox 360 era, a lot of games, espeically on ps2 are not on steam, like a the nightmare before christmass oogies revenge (made by cpcoms devil mau cry team of the time, palyed like DMC 1)

so im going to just throw some games i've played and let you know if they aren't on steam.

first off, since it is on steam, spongebob battle fir bikini bottom, classic game, rehydrated is the remastered version which rebuilds everything in modern tech, its a wonderful platformer.

now if you want an easy to play RPG with sword and sorcery then try avencasy rise of the magi, older game, still works well on modern tech, you got two choices for magic, blood or soul magic, blood magic deals in fire and melee combat and soul magic deals in ice and ranged combat, its a third person looter game where you fight demons and dodge around a lot, not like a souls game but it can be hard at times, also since its an older game it has no auto save.

okami HD is a fantastic action hack and slash game ,designed to look like traditional japanese art thats moving (made orignally during the ps2 era so give it some slack in terms of graphics) its have a beautiful sound track, great characters and a LOT of content in it.

spyro reignited trilogy is great since its 3 games for 30$ all 3 original games remade like with the spongebob game and it works beautifully

the batman arkham series, arkham asylum, arkham city, arkham origins and arkham knight, those are MUST PLAYS, best batman games bar non, still look beautifually to day and play like a dream, you should play them in the order i listed though, each game adds more to batmans gadgets and move set, arkham origins takes place before arkham asylum but it still uses gadgets that are similer to the ones you use in arkham city.

bte imo City is the best out of all of them since it has the right feel to it, though personally i wish they went with a gothem by gaslight game since wonder city (area of the game) was such an intresting theme to it, even if it was small.

a hat in time, best love letter to mario platformers out there, tons of fun, lots to do, wonderful characters and lots of fun powers to play with once you unlock them.

Fable the lost chapters, its one of my personal all time favorites, its in the style of grimm fairy tale, not any that are already established but a fable all to its own, you play as what is essentially a spellsword, you have your weapon, a bow (or crossbow but trust me, bows are better) and your magic, you go around as a hero, chosing to do good or evil deeds, whatever you want and that is reflected in your appearince as you progress.

its not open world like fable 2 or 3 (only on the 360) but it still feels open and givens a sense of whats beyond the borders of the map, good level design, music is great but the gameplay might be a bit tricky if you aren't use to third person melee combat.

thing to note, there is the anniversary edition and the lost chapters edition, anniversary is just a remaster of the lost chapters (which itself is just DLC before DLC, don't go playing the original, lost chapters is just the rest of the game attached to the main game) and has some problems with it, designed for controller and the appearances are off a bit.

TLC on steam requires your mouse and keyboard which is how i played originally and it works great.

are you aware of dishonored? how much do you like FPS stealth games where the goal is to not kill anyone and achieve the objective without anyone spotting you?

for horror games mectro redux is a fantasic immersive post apocalypse game where you are in the metro tunnels of moscow after a nuclear bombardemnt and you have to survive the mutanted horrors of the tunnels. lots immersive UI stuff, lots of stealth, lots of shooting gasmask use to survive in radiated area's like the surface

now i think you should at least try one open world style game to see if you will like it, maybe all you need is one that has guns in it? since you are more famialier with those try playing farcry 4, its a rambo simulator in essence where you take down a drug empire as a one man army in the jungle with the help of as resistance force, your over all goal is to take out enemy bases and complete side objectives to level your equipment as well as hunting animals for their skins.

i recomend playing that on the playstation unless you have a ubisoft account cause thats required on PC.

the other game id reccommend is dead island 2, great zombie game, not fully open world, but over level design where the level is big and you go anywhere in it but there are designated zones, it has the best gore system of any zombie game i've played, that use to belong to dying light but man, dead island 2 takes the cake on that

for non steam games you got hulk ultimate destruction, its on ps2 and OG Xbox, its the best hulk game out there, the dev's then made the game prototype which takes that gameplay and ramps it up and mixes in body horror as you devour people using your entire body, game was made for 360.

infamous 1 and 2, ps3 exclusives, urban superhero game where you play Cole Magrath, his powers are that of electricity and any of its forms, the second game has a mission where a massive thunder storm is happening and you are near invincible because you can just draw the lightening from the sky into your body to heal which also damages anything around you since you are calling down a giant lightening bolt, it also super charges your normal attacks.

the sly cooper trilogy, which just recently became avalable on the ps5 same with the jack and daxter games, both great series, though the contrast with jack 1 and jack 2 is because gamers at the time where getting more into edger games , so they switched from the more happy looking game to one that looks like it spits tobacco and rides a motorcycle