| Microsoft Home Mouse | 1995 | I.B.M and Compatibles | Mouse | Serial | Microsoft Corporation |
| MDA STK86C340 | 1991 | I.B.M and Compatibles | 8bit ISA | CGA Graphics Card | MDA Graphics Card | Parallel Port | Unknown Manufacturer |
| Music Quest PC Midi Card | 1992 | I.B.M and Compatibles | 8bit ISA | Midi Card | Music Quest Inc. |
| Madge Networks Token Ring | 1996 | I.B.M and Compatibles | PCI | Token Ring Card | Madge Networks |
| Matrox MGA-2164WP-C | 1997 | I.B.M and Compatibles | VGA Graphics Card | PCI | Matrox Graphics Inc. |
| Matrox MGA-2164WA-B | 1997 | I.B.M and Compatibles | VGA Graphics Card | AGP | Compaq Computer Company | Matrox Graphics Inc. |
| MGP VI MS61C88 | 1989 | I.B.M and Compatibles | 8bit ISA | CGA Graphics Card | MDA Graphics Card | Parallel Port | Unknown Manufacturer |
| Microsoft InPort card | 1986 | I.B.M and Compatibles | 8bit ISA | BUS Mouse Card | Microsoft Corporation |
| Multi I/O Card | 1987 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Serial Port | Game Port | RTC Card | Unknown Manufacturer |
| Multi I/O Card | 1989 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Floppy Controller | Serial Port | Game Port | RTC Card | Unknown Manufacturer |
| Microsoft Serial-Mouse Port Compatible Mouse 2.0 | 1994 | I.B.M and Compatibles | Mouse | PS/2 | Microsoft Corporation |
| MDA / CGA Graphics Card | 1988 | I.B.M and Compatibles | 8bit ISA | CGA Graphics Card | MDA Graphics Card | Parallel Port | Unknown Manufacturer |
| MDA Graphics Card | 1988 | I.B.M and Compatibles | 8bit ISA | MDA Graphics Card | Parallel Port | Unknown Manufacturer |
| MDA Graphics Card | 1992 | I.B.M and Compatibles | 8bit ISA | MDA Graphics Card | Parallel Port | Unknown Manufacturer |
| Multi I/O Controller Card | 1995 | I.B.M and Compatibles | 16bit ISA | Parallel Port | IDE Controller | Floppy Controller | Serial Port | Game Port | Winbond Electronics Corporation |
| Multi I/O Controller Card | 1993 | I.B.M and Compatibles | 16bit ISA | Parallel Port | IDE Controller | Floppy Controller | Serial Port | Game Port | UMC |
| Multi I/O Controller Card | 1999 | I.B.M and Compatibles | 16bit ISA | Parallel Port | IDE Controller | Floppy Controller | Serial Port | Game Port | Unknown Manufacturer |
| MPX2 Ethernet Card | 1996 | I.B.M and Compatibles | 16bit ISA | Ethernet Card | Unknown Manufacturer |
| MPX2 Ethernet Card | 1995 | I.B.M and Compatibles | 16bit ISA | Ethernet Card | Unknown Manufacturer |
| Microtek Inc. HDC1000 | 1986 | I.B.M and Compatibles | 8bit ISA | MFM Controller | Microtek Inc. |
| Multi I/O Card | 1985 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Serial Port | WYSE Technology |
| Multi I/O Card M10-100 | 1987 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Floppy Controller | Serial Port | Game Port | RTC Card | Unknown Manufacturer |
| Mountain IBM QIC-02 | 1983 | I.B.M and Compatibles | 8bit ISA | Tape Controller | Mountain |
| MDA/CGA Graphics Card | 1988 | I.B.M and Compatibles | 8bit ISA | CGA Graphics Card | MDA Graphics Card | Parallel Port | Unknown Manufacturer |
| Multi I/O Controller Card KT-105F | 1990 | I.B.M and Compatibles | 16bit ISA | Parallel Port | IDE Controller | Floppy Controller | Serial Port | Game Port | Winbond Electronics Corporation |
| Multi I/O Controller Card KT-105F | 1992 | I.B.M and Compatibles | 16bit ISA | Parallel Port | IDE Controller | Floppy Controller | Serial Port | Game Port | Winbond Electronics Corporation |
| Microtek Inc. HDC1000 | 1987 | I.B.M and Compatibles | 8bit ISA | MFM Controller | Microtek Inc. |
| Multi I/O Card DIO-500 | 1988 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Serial Port | Game Port | Unknown Manufacturer |
| Multi I/O Card | 1990 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Serial Port | VIP |
| Multi I/O Card 301/302 | 1992 | I.B.M and Compatibles | 8bit ISA | Parallel Port | Serial Port | Game Port | Winbond Electronics Corporation |