Hexadecimal numbers are offsets from the beginning of the NES ROM. As are decimal numbers. Hex numbers are preceded by $. Note that your .nes file probably has a 16-byte iNES header, and this header is not included in determining the offsets below.
These are notes and not guaranteed to be correct. More to come when I get it formatted. Tiles. Here is where images are stored. This section starts at $c11b (the first meaningful tile image -- a stairwell). These are in PRG ROM 3, which starts at $c000 See Tril's specs and other resources for more information.
$ce3b [52795]: armos
$ce7b: bush
$cebb: rock
$cefb: right-pointed rock
$cf3b: left-pointed rock

53947: inverse armos (the living one)
54011: armos from behind (left foot up)
54075: armos from behind (right foot up)

54203 and surrounding: octorok
54267: octorok with mouth pulled in, ready to shoot
54331: ?

54619: lynel (centaur-like)
54683: lynel with front and back legs together, running

54747: goriya
54811: back of goriya