For US
Vegas Technology – Casino Coins best, Golden Casino Ok
Rival – Absolute Slots, SlotoCash and ThisisVegas, in that order.
RTG (VERY Select Operators as this is a minefield, good software MANY suspect operators).
New ones I am evaluating that look promising:
CardSpike – Take All US Players, Only Cake Poker Room that has full Casino, Strong Processing
TopGame
Wizard