If you're looking for sarms, osta (not my personal favorite but many like it) and/or gw (cardarine) are definitely your best bets.
Personally, I would opt for cardarine as its not going to cause suppression. You could even stack this with a normal stimmed and/or non fat burner like alphamine/lean edge.
Phwsupplements also has a whole slew of other fat burners like norcodrene or shift (both PES) as well as some of the last sarms around (and a 15% discount on most of them using code SARM15, FOCUS15, or PRIME15 depending on the brand).