Why another LiPo charger?
A lot of hobby projects rely on ultra-cheap LiPo chargers (eg. TP4056) but they are typically quite disappointing and if used to charge the device at the same time as powering it frankly dangerous as the charge may never terminate.
The Texas Instruments BQ25186 "1A I²C-controlled linear battery charger with power path and solar input support" has most of what I think is important in a more fully featured project including software driven 'shutdown' and battery undervoltage protection.
Previously I've used the MCP73871 but that is an old part now and this seemed like a good replacement. An added bonus is supporting more battery chemistries including LiFePO4 which I can see myself using the future. It doesn't include a fuel gauge but not every project needs one and we've always got the option of using an ADC GPIO and a resistor ladder as an admittedly somewhat inaccurate rough gauge.
No breakouts were available beyond the official TI one, so I made some myself. This way I can prototype an upcoming battery powered project with it before finalising the design.
These are now for sale on Tindie and I have written a pretty comprehensive Arduino Library for configuring, monitoring and managing them.