IDEX and Etherdelta just for ethereum based tokens, dex.wavesplatform.com you can login with your waves account and trade with pair btc, eth and waves.
You can trade on Waves DEX but the volume is very low (
https://coinmarketcap.com/exchanges/waves-dex/)
The top coins with highest volume based on the link above are top coins, which is also available in most centralized trading sites, so why would one use this? This exchange would be very useful if waves tokens are traded with liquidity, but unfortunately it's not currently.