Check out gen.lib.rus.ec, the only library i need
I mostly use Exsila to trade my old books and CDs to the ones in which I am currently interested (at the moment mostly children books for my daughter).
It’s nice to not throw away my old stuff. At the same time I get the old stuff from others that I would need to buy.
Unfortunately, there are not too many English books on it but I hope that might change with some time.
If you are interested, you can use my referral link to get some starting balance: