You can currently swap any of the following tokens:
ETH & TKN
Stablecoins: DAI, SAI, USDC, USDT & cDAI (interest-bearing DAI thanks to Compound (https://compound.finance/)
Tokens: ANT, BAT, BNT, DENT, ENG, ENJ, GNO, KNC, LEND, LINK, LRC, MANA, MCO, MKR, NEXO, NMR, NPXS, PAX, PAY, POWR, REN, REP, RHOCC, RLC, SNT, VERI, wBTC, WTC & ZRX.
We will progressively expand the number of tokens available to swap - feel free to suggest the ones you would like to see.