There seem to be two subclasses of very similar boards:

1. Boards that are completely equivalent wrt usable pins / connectors and resources and only differ in exact fpga model (usually size and / or speedgrade). These include the tinyfpga_ax{1,2} and the zturn_lite_z0{07s,10}.
   Currently these are handled as different boards, located in different files. The zturn_lite uses inheritance to avoid duplicating the pinout.
2. Boards that are very close but still differ in resources (due to for example different sets of usable pins on different fpga models). These are currently also handled as completely different boards (for example the ecpix).

The approach of making every variant its own board currently seems to bring two main advantages:

1. Its hard to use the wrong board (by accidentally using the wrong fpga model or speedgrade)
2. Each variant is (apart from the zturn_lite) is completely seperate from each other, making maintance easier (changing a variant only ever affects that variant).

Considering these advantages the approach for the second class seems very reasonable already.

For the first class however it might be better to put them in the same file and use inheritance like the zturn_lite to avoid duplicating pinout, programming logic and more.

Especially for speedgrade however this still seems a bit unnecessary and could bloat the list boards.