Here's my current requirements list, however I've only included classes that I've travelled on one or more unit of, others will be included as and when I travel on one or more units of any unlisted unit classes.
DMUs
Pacers
Class 142: 37 (24x Northern, 13x ATW)
Class 143: 21 (13x ATW, 8x GWR)
Class 144: 8
Sprinters
Class 150: 104 (31 x ATW, 38x GWR, 3x London Midland, 32x Northern)
Class 153: 64 (5x AGA, 7x ATW, 17x EMT, 14x GWR, 7x London Midland, 14x Northern)
Class 155: 2
Class 156: 79 (9x AGA, 15x EMT, 24x Northern, 31x ScotRail)
Class 158: 114 (23x ATW, 6x EMT, 15x GWR, 16x Northern, 44x ScotRail, 10x SWT)
Turbostars
Class 168: 23
Class 170: 116 (12x AGA, 26x CrossCountry, 19x London Midland, 51x ScotRail, 4x Southern, 4x TPE)
Class 172: 38 (4x Chiltern, 26x London Midland, 8x London Overground)
Coradias
Class 175: 12
Class 180: 10 (3x GC, 3x GWR, 4x HT)
Desiros
Class 185: 31
DEMUs
Voyagers
Class 220: 33
Class 221: 43
EMUs
PEPs
Class 313: 58 (39x Great Northern, 19x Southern)
Class 314: Class cleared
Class 315: 57 (17x London Overground, 40x TfL Rail)
Class 507: 4
Class 508: 5
Mark 3 derived
Class 317: 71 (46x AGA, 11x Great Northern, 14x London Overground)
Class 318: 16
Class 319: 66 (7x London Midland, 59x Thameslink, Northern 319/3s cleared)
Class 320: 18
Class 321: 111 (94x AGA, 13x Great Northern, 4x ex-London Midland, Northern 321/9s cleared)
Class 322: Class cleared
Hunslet TPL EMUs
Class 323: 33 (25x London Midland, 8x Northern)
CAF-Siemens EMUs
Class 333: 9
Junipers
Class 334: 39
Desiros
Class 350: 66 (66x London Midland, TPE 350/4s cleared)
Class 380: 32
Networker EMUs
Class 365: 39
Eurostar EMUs:
Class 373: 56
Class 374: 32
Electrostars:
Class 377: 236 (31x Thameslink, 205x Southern)
Class 387: 55 (27x Gatwick Express, 28x Thameslink)
Pendolinos:
Class 390: 49
LIGHT RAIL
Manchester MetroLink: 115
Nottingham Express Transit: 33 (13x AT6/5, 30x Citadis 302)
Sheffield Supertram: 1