I don't know about the rest of the series, but the 100 was my first 'Book, hence my longtime love affair with the later Duos.

The only internal expansion or acceleration option I can recall, other than the modem, was a (RAM interfaced) Video Card for the 100. Dunno about the rest of the series, I used BabyPB until I was forced to move to a used Duo 230 because the 68000 was no longer supported by newer versions of primary apps..