New game system

Is it possible to put a new game system in thats not based on D20? I been looking and i can't get a clear answer on it. If so, can someone point me in the right direction?

IF you mean in the drop down listing when you create a campaign, you need it to gain popularity and be seen playing in multiple instances on a regular basis on roll20 then it would be in the consideration of being added when the devs decide to update the list. If you mean in how to create a character sheet, macros, and other things? You would have to supply information about the system mechanics so that people would know how the dice rolls worked.

Almost any game can be played on Roll20, despite the name.

Yes.

Roll20 is called "system agnostic" meaning it simulates a blank table at your house, so you can put whatever games you want to play. Roll20 has dice, cards, drawing, pictures, tokens, miniature figures, graph paper, hex paper, chat room text, voice audio, webcam video. Making your own "campaign" (starting a game) is FREE and unlimited, so try it out. Click "Create Campaign", and then Launch it to enter your own private virtual tabletop. You can write things in your own chat room. Draw smiley faces on your own tabletop. Invite friends with your own private campaign link. Then you can test it out as much as you like, and see how to make your games work here.