speed values:
sidehop: 28. instant acceleration, 3 frames of 0 speed every 15 frames (on flat surface), for an average of 23.33.
sidehop roll: 23
backflip: 24. same acceleration as sidehop, average speed of 20
running: 23
walking sideways: 13
backwalk: 13
crawling (~5 average, changes every frame)
walking forward with L target: 16.1
jump slash: 25
spinner: 26
iron boots: 3.68
iron boot roll: 10 (same (de)accel rate as normal roll, though you'll get 10 speed right from idle)
iron boot sidehop: 28 (5 on, 3 off on flat surface, for 17.5 average speed)
iron boots backhop: 25
autojump off a ledge: 21.6
Walking with ball and chain: 3.68
shield attack: 14
sidehop roll: 25
magic armor with no rupees: same as iron boots. also wearing iron boots in addition to magic armor doesn't slow you down at all.
good LJA: 72
flat ground lja: 36
LJA from target over lower elevation than link: 15-30
less shitty lja, but still not good: up to ~56?
swimming: 8
swim dash: 13
swim while sinking with iron boots: 1.28. If you take iron boots off, it increase by 3 every frame until it reaches 8. If you put them back on speed drops by .5 each frame until reaching 1.28
swimming up: 22 (increases by 3 every frame up to 12, then accelerates by .75 every time you press A again). Drops back to 0 if you don't press A for 32 frames. Once you hit 22 speed, you only need to press a once per second to maintain it.
zora armor swimming: 14
zora armor fast swim: 22
running speed from idle: 0,0,0,0.046,1.06,1.66,3.06,0.96,3.29,6.56,11.2,16,19,20.9,22.8,23,23,23,etc
underwater with iron boots:
roll: 7.5
sidehop: 8.4
rolling: 7.5
backhop: 7.5
walking: 14.7
jumpslash: 7.5
rolling:
with speed <= ~10 (9 frames from standing still): 25
with speed <= ~15: 27.7
speed >= ~22: 32.9
(there's more tiers, but since only the first and last even matter, i'm not testing them all)
roll acceleration from 23 speed run: 23, 32.9*15, 31.9, 30.9, 29.9, 28.9, 27.9 repeated. Average speed is 32.15
average roll speed from idle, to 22.8 run speed, then rolling, after 3 rolls: 27.14048
Average roll speed from idle, after 3 rolls: 27.73047619
Rolling right away also accelerates much faster (jumps right to 25 speed), so that third roll happens much quicker. So it is always best to roll on the first possible frame (except on the second roll, wait 3 frames to max out speed).
epona:
running: 35 OR 42.
dashing: 50 OR 73, depending on area...
epona slide: 73
wolf:
running: 25
dashing: 33 OR 45. After pressing A, it goes to 65 for 1 frame, then drops to 59,53,47,45. Otherwise it never changes. It appears this depends on where you are (?). In some areas it's 33, others it's 45. When it is 33, you get 1 frame of 35 speed then right back to 33 after pressing A. This has instant acceleration, regardless of how fast you were moving before.
sidehop: 33
backhop/flip: 30
backwalk: 12
sideways walk: 22
walk forward while L targeting: 22
jump attack: 26
B attack while moving: 30
swimming: 9
swimming (dash): 20. 3 speed/frame acceleration, then stays at 20 forever.
autojump: 22.34
wolf run acceleration: +3 per frame until it reaches 25.
Memory addresses appear to change every time you change areas or watch a cutscene, but values are consistent and easy to refind...
tl;dr here is it's always fastest to roll on the very first possible frame. A single sidehop is also faster than a single roll, from idle, but that's probably never useful. Wolf speed depends on where you are, and it sometimes only just barely faster than rolling.
There also may or may not be situations where LGAing (off enemies only, throwing the boomerang is too slow) could be faster than rolling.
After the 29 speed roll you get 32.9, just like if you got up to full speed before rolling. You'll notice that at no point is running first faster. It's not even close.