Looks like the right one is available on Amazon here.
[link|https://www.amazon.com/5100mAh-Replacement-Internal-SM-T387V-EB-BT367ABA/dp/B083BY2PG2|Amazon.com: 5100mAh Replacement Internal Battery for Samsung Galaxy Tab A 8.0" (2018) SM-T387V Verizon EB-BT367ABA with 17in1 Repair Tools : Electronics|new_window=true]
On the other hand, eBay has it a LOT cheaper.
[link|https://www.ebay.com/itm/164195087572|New Battery EB-BT367ABA for Samsung Galaxy Tab 8.0 SM-T377 SM-J700 SM-T550 712317097399|new_window=true]
Basically, if you do a search for the part number of the battery itself, you come up with a lot of options. A simple search string that works well is "samsung EB-BT367ABA".