35mm became the most popular choice in film formats of all time. Ilford, Kodak and a few others are still available and will be added here.

Kodak Tri-X 400TX 35mm 36 exposure 400asa Black & White Film 5 Pack

5 rolls
400ISO
36 Exposures
About £32

Kentmere 400ASA 135-24 Pack Of Three

3 rolls
400ISO
24 Exposures
About £16

Ilford HP5+ 400asa 35mm – 36 exp

1 roll
400ISO
36 Exposures
About £7.50

Ilford HP5+ Black & White Film, 24 exp, multipack of 5

5 rolls
400ISO
24 Exposures
About £23

Ilford 1574577 HP5 Plus, Black and White Print Film, 35 mm, ISO 400, 36 Exposures

2 rolls
400ISO
36 Exposures
About £15

Kodak 8667073 Tri-X 400 135/36 Negative Film – Black/White

1 roll
400ISO
36 Exposures
About £7.50

Ilford XP2 Super 135-24

1 roll
400ISO
24 Exposures
About £5

Ilford XP2 Super 135-36

1 roll
400ISO
36 Exposures
About £6

ILford FP4+, 35mm/36 exposures, 5 rolls

Ilford HP5+ 35mm, 36 exposures, 5 rolls

5 rolls
ISO400
36 Exposures
About £27