If you need some ideas for free form hit me up on PM and I can try to send you some of the stuff we use. For some of our games (our main game in fact) we use poker decks and a 1d10 or 1d100 based system of skills and power with players using playing cards instead of dice.
One of the best parts is if I don't want the players to know their own rolls on something (figuring out a trap or understanding a riddle, finding a clue) they show me the card face forward. This alleviates me rolling for them, and also keeps them subtly guessing on if they truly succeeded or not. It added a level of player interaction that is missing in many games, or has to be planned in advance or even require a place to roll
With cards, we have 7 people sitting in beanbags, laying down, sitting up, standing and explaining their moves, whatever, with the cards allowing for instant rolls and no need for surfaces.
There is never the certainty of something unless they succeed by a great deal or they critical pass a test (joker or whatever face card you decide pregame). However, due to them not seeing it some rolls, they then can use skills that they have to ascertain or understand if what they THINK is going on really is. We found this also allowed us to add skills to our skills list that frankly get lost in some games due to them not seeming to have a connection to the game style at that time. As I said its a bit hard to describe and you do have to spend a couple hours trying to decide how you want the rules to flow and how deep you want to go, but due to the very nature of the card system it is so fast that even if you want to make a good deal of complexity it doesn't matter because its so fast and there is so much more flexibility that you can do that if you want.
In addition it fucking makes battle amazing. In our games, some player classes can learn combos or special moves, spells, skills that are a set move 1 2 3 kind of thing like jab jab cross lets say. For this They draw say...3 cards and lay them out, that is their three parts of an attack combo. Then I draw mine without them seeing. And I go on to explain what happens with no needed breaks and embellishing and running easy numbers in my head all in one seamless narrative, even if, for example, they have a failure on their second jab but their cross card was high. This seems to have created a very real heroic, strangely satisfying removal of the tit for tat that a good deal of games have in battle. We can still do that kind of thing if we want, but when we don't players have explained to me that it finally feels like the way roleplaying should, with free flowing combat that is very fast, really cinematic and still is pretty safe from being abused and when you do finally get a special move, or create your own(after training), you feel like it is yours, but there is still the chance that it may not go perfectly but still succeed. It is that gray area that we were finding was missing in many rules systems.
Basically it seemed to increase the roleplaying aspect of the game back to something far more interactive, the ease of using the play area itself increased tremendously, it returned some of the mystery to the game, and also made the battle sequences far far more enjoyable than any of the 15+ systems we had used in the past 21 years.
It is the rule system we use in our long term Fading Suns+Warhamer 40,000 game as well and has stood the test of time and...I think maybe 14 total players. And even those that have left our group, moved away and such, all use it now. Its been a pretty fantastic discovery for us.
Obviously this isn't for everyone. Even my players at first, really enjoyed their dice
and didn't want to move on. But it's benefits are many and so far, its weaknesses seem to be...none other than the players going from playing 1 time a month to 3.