I would suggest the WM9999-ND as a general-purpose tool usable with a connector of this type as well as the similar “F-Crimp” ( also called a B-crimp) style commonly found on uninsulated spade terminals, 1/4" quick disconnects, etc. It’s an unofficial, non-ratcheting tool type that is nevertheless inexpensive by comparison to many, and which can be made to work with an extremely wide range of contacts due to the variety of cavity sizes it offers. Excellent toolbox item.
The heart-shaped cavity opening when the tool is closed is an indicator of a tool designed for use with this style of crimp; the open ends of the contact are positioned against the side of the cavity having a sharp point, so that they are folded inward and together as the tool is closed. For production work a ratcheting type tool may be preferable for various reasons, but with some care it’s quite possible to get respectable results with a cheap type of the sort mentioned.