Watson Lithium-Ion Battery Pack (3.7V, 1800mAh) for HD B-1801
PKCELL Flat Top 14500 Li-Ion 3.7V 800mAh Rechargeable Battery
Amazon.com: PKCELL ICR18500 Battery 3.7V 1400mah Li-Ion Rechargeable with Button Top 6PC(They are not 1865mm Batteries Also Not AA Size Battery) : Health & Household
Lithium Ion Polymer Battery with Short Cable - 3.7V 350mAh : ID 4237 : $5.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Amazon.com: AKZYTUE 3.7V 2200mAh 604368 Lipo Battery Rechargeable Lithium Polymer ion Battery Pack with JST Connector : Health & Household