Currently the LP rate for several pools on Sifchain are 300% APR fixed, that comes out to over 2,000% APY if compounding daily or weekly. The team plans to allow daily rewards claiming soon and that will enable higher APY. Every 4 weeks the Sifchain community will vote on which pools will get the 300% APR. I have staked with ATOM/ROWAN pool because it is the largest pool by total volume and will likely continue to be selected for the high APR pools.
See my earlier blog post on how to participate in Sifchain LP