Urban Rivals has very unimpressive amateurish graphics and a very simplistic battle system, but the actual level of strategy and depth that goes into deck construction and playing an opponent is quite significant. You have to be a big fan of out thinking/predicting your opponent more so then throwing together crazy combos cause that's really the name of the game, you both see each others hands at all times so the trick is in getting inside your opponents head, figuring out what they're likely to do, and doing something that best counters that, not in slowly setting up some flashy combo. Urban Rivals also gets big props from me for being very easy to play theoretically forever for free, or even easier to play for ever if you spend 1.50 (the minimum purchase amount). Once you spend atleast some money you get access to the market where you can buy and sell cards with the points you get for playing the game. Combined with the occasional free card give aways and the cards you get at every 5 levels, not to mention that a deck need only be 8 cards in size and you need only a single copy of a card to run it, its very easy to play this game getting tons of new cards all the time spending very little money.
Ederon is another online tcg, the game seemed pretty good, the graphics were ok though not on Alteils level, but its biggest knocks were the rate of distribution of free cards, and the player base (the former leading to a situation with the latter). Aside from your starter deck the only way to get free new cards (obviously you could buy packs) was to level up (free cards at each level up), but you actually lost experience points if you lost meaning you couldn't just grind you way to high levels, you had to already be winning alot. To make matters worse until you spent your first amount of money you were level capped at 5, AND the first payment you paid was just to "buy" your starter you started with, plus like maybe one extra pack or something. The result was that there weren't many free players, and with out a large free player base, there weren't many opponents for the paying players. That pushed me away from the game.
Kongai is another simple one like Urban Rivals, (your deck consists of only 5 cards), but the graphics are amazing and like Urban Rivals its definitely a skill game thats all about reading your opponent and being better at figuring out what he's going to do then he is at figuring out what you will do. Like Alteil their are what amounts to treasure battles, though they seem to happen much more frequently and aren't based on win streaks. In addition to getting new cards through that method they also have weekly challenges where you can do other tasks (such as beat their ai opponent x number of times or play one of their other minigames and get x score) to win free cards. From what I've seen it looks like the game doesn't even have packs, if you want to spend real money you buy everything as singles which is another plus. Only real downside is the game seems to be strongly ad supported, but they've never bothered me.
Mysteria is from the same group that company that does Kongai, I wouldn't have even found it except a recent kongai challenge to win a card was to play through Mysteria's single player campaign and beat one of its challenge mode challenges. To me it feels like a magic the gathering knock off, and a relatively poorly balanced one, so it didn't wow me, but for what it is it is decent and its nice to see an online card game with a significant single player tutorial and campaign. I didn't look into it too much so I don't even really know how you go about getting new cards, I think maybe from beating challenge mode challenges, but I was happy to see that its one of the rare games that lets you start with the starters for all of the games "spheres" so it was nice to switch between them with out having to make a new account. Like Kongai it was pretty clear that the majority of the profits are intended to come from their ad sponsors.
Cardmaster Conflict, played it once, didn't care for it. Ironically I started with the games first set light starter so based on Azul's comment maybe I just made a bad choice in starter and thats what turned me off to the game. Regardless theres a serious problem if a game allows a starter to exist that flat out turns players off from the game if they choose it.
Magic the Gathering Online, played it many years ago, don't believe there was any ways to get free cards back then, seemed too expensive to me to get new cards with out some free ways to get things so I lost interest.
YGO, played it many years ago, freakishly expensive to play (paying per duel, I can't even keep playing with the cruddy cards I already have, what the heck?) and the game was using the old yugioh cards back when the game was horrendously unbalanced. Maybe its better now but I haven't had any desire to look into it again.
The bunnies of Lavato have special abilities, like 'Action Skill: Make Carrot Disappear.'