CMP170HX, best hashrate and power efficiency (160Mh/194W). IIRC A4000 is the next one efficiency wise.
If you can find them, of course.
I've never seen any of this CMP graphic cards in stock before I believe they are extremely rare than even the RTX non LHR GPUs anyways it doesn't matter anymore because crypto market is not stable again so mining will surely be less profitable
These are never available in retail stores, you have to shop Chinese datacenter suppliers. A4000/5000, however, can be found in retail.