1. Fortunejack: dash,ppc, clam, xmr, doge, ltc, nmc, nvc, zec, rdd,eth
2. Bitsler: doge, eth, ltc. burst
3. Crypto-games.net: dash, doge, eth, grid, ltc, xmr, ppc, strat
4. Luckygames.io: it accepts 40 cryptos, you can check it on their site
5. Bitdice: doge, ltc. eth
6. bitvest.io: ltc, eth
Actually there are some others, but above sites are my favorite.
I second that list.
However it makes you think. Why don't any of these sites ever accept USDT tether?
Basically with BTC at $17000 and $10000 last week, it would make sense to accept USDT so its pegged at least to the dollar.
Because what will happen when BTC starts going back down, and alts are going back up? Also the transaction fees are crazy high at the moment for BTC. Pretty much $20 to send a single 1 input 2 output transaction.