Sandals & Ankle Boots
Sandals
The only Jem shoes that had left and right differences, making them even more difficult to pair! All of the first year Flip Side fashion sandals came in two different versions which are 1) rubbery ones with "flush" straps & right/left designations, and 2) harder plastic ones with the "attached" straps. Boxes that are marked H44 came with the "attached" straps style shoe, the flush straps came in H22 marked boxes. (What does this mean?)  Unfortunately, the rubbery ones have a tendency toward fading & staining so the colours can vary somewhat.
Luckily the shoes are relatively easy to figure out which fashion they go to, as they have pretty significant differences in colour. 
White (flush straps)
Only came with


Pink & Lavender
Lavender only came with 
Some LTMP came with pink shoes. I have also seen lavender shoes that were mottled with pink. I believe they are probably faded lavender shoes, though I can't say for certain. 

Pink 
Came with the following fashion
Besides the possible Let The Music Play variation, there is some colour differences between the pink shoes for Gettin' Down To Business, see below left. Since no other outfit or doll comes with the pale pink colour it's easy enough to identify them as being for Gettin' Down To Business.


Dark Pink
There are two different shades, those from Set Your Sails are warmer, nearly salmon coloured. How You Play the Game are cooler pink. I had these fashions in Canadian packaging with the shoe colours reversed.
Plum
Only came with

Blue
Came with
Left to right:
Cornflower Blue (Sophisticated Lady)
much greyer than those from Rock Country. These are the rubberier shoes with the flush straps.
Blue (Sophisticated Lady)
Much more vibrant tone than the grey version.  
Turquoise Blue (Rock Country)
Bright, vibrant turquoise.
(Not pictured) Rock Country flush straps version
Also a bright turquoise, doesn't vary too much in colour from the attached-straps version.

 Yellow

This is the trickiest colour to ID among sandals. Easiest to ID is the flourescent yellow, from Outta My Way. Let's Rock This Town is the only one to have the attached-straps yellow sandals which are also a darker yellow than all the rest. The flush-straps version from that fashion (not shown in photo) is rather orangey. Which leaves us with the canary yellow shade, which is for Just Misbehavin'.
  • I have been told of Flash 'n Sizzle Jems with yellow sandals, the same colour as the pumps she normally comes with.
Orange (both flush and attached-straps versions, attached version shown)
Came only with
Ankle Boots
There are only six different pairs made.  Rubbery ankle boots, came only with Synergy, Flash 'n Sizzle Jem/Jerrica and the Music is Magic fashions. Flash 'n Sizzle Jem/Jerrica and Synergy's boots are noticeably thinner and more flexible than the boots that came with the fashions.
Light Raspberry Pink. Thin and flexible.
Came only with
Raspberry Pink stiffer than the boots that came with Flash 'n Sizzle Jem/Jerrica and Synergy.
Came only with
Dark Pink, stiffer than the boots that came with Flash 'n Sizzle Jem/Jerrica and Synergy.
Came only with
Red Violet. Thin and flexible.  
Came only with
Here's a picture of some strange matte Synergy boots!
Purple, stiffer than the boots that came with Flash 'n Sizzle Jem/Jerrica and Synergy.
Came only with
Aqua, stiffer than the boots that came with Flash 'n Sizzle Jem/Jerrica and Synergy.
Came only with

Credits: Thanks to Jaze for the photo and information about the Let The Music Play pink shoes. Thanks to Lynda for the Gettin' Down To Business colour variations photo. Flash 'n Sizzle Jem sandal info thanks to Alex. Thanks to Isabelle for the matte Synergy boots photo and information. Thanks to Rhonda Robinson for the photos of the boots from Rock 'n Roses, Splashes of Sound and Star Struck Guitar.