For MIDI you can either use a true Roland MPU-401 only card (various models exist: ISA, MCA, NEC & other platforms). You can then hook up virtually any external module (both Roland: MT-32, CM-300, SC-7, SC-55 and so on but also Yamaha: FB-01). There are MPU-401 clones out there that can be bought relatively cheap sometimes (when you are lucky). The cheapest Roland ISA cards with wavetable (GM: Roland RAP-10 & SCC-1) support most games. You can then choose to hook up a MT-32 for the older games that support it through the perspective MIDI box (MCB-1 for LAPC-I, MCB-2 for LAPC-N, MCB-3 for SCP-55 and MCB-10 for RAP-10). I would not recommend using a sound card that states that they have MPU-401 (through a game port connection: that usually does not work very well). With the SCB-7 (SCD-10) and SCB-55 (SCD-15) daughterboards you can also have true MPU-401 for games through a good Sound Blaster 16 (check the revisions topic: some versions of the SB16 have a hanging note issue).
The Yamaha FB-01 is a fun simulation of the IBM PC Music Feature that is supported by a very limited set of early Sierra games. It connects through regular MIDI.