The TeamGroup MP44 internal SSD's benchmark results make it a good boot-drive candidate for a budget or mainstream PC, though its random write speeds keep it from the top of the performance pack.
The SSD 990 EVO is an excellent-value mainstream M.2 internal SSD, with whizzy performance and the class-leading warranty, software, and security that you'd expect from Samsung.
The Corsair MP600 Elite is inexpensive and available with an optional heatsink for a small premium, but uneven throughput performance holds back this DRAM-less M.2 SSD from excellence.
The Addlink AddGame A93 is a high-performance, inexpensive internal M.2 SSD that's great for gamers (or anyone else) upgrading or building a new PC on a budget.