MacBook White Unibody > Internal Drive Brackets and Caddies

The "Unibody" redesign of the MacBook, introduced in 2009, is a decently upgradeable machine. The 2010 revision, which can be upgraded all the way up to 16GB of RAM, is clearly the superior model, but even the 2009 machine can go to 8GB and both of them can run an SSD at useful speeds with their SATA 300 controllers. A cheap upgrade to 8GB of RAM and a small SSD make them perfectly capable of performing light home and office type tasks, even more than 10 years after they were launched. Though they are of course not comparable to modern machines in terms of processing power.

There are some requirements to use 16GB in the 2010 models, but the vast majority of models will already meet them.

All these machines max out at macOS 10.13 High Sierra.