Forwards pull hipbelt
Easier to tighten then a regular back pull hipbelt however the smaller 25mm buckle can be harder to use if wearing gloves.
Adds $25 to pack price.
Solid front pocket
Replace the front mesh pocket with a solid Gridstop fabric. The mesh can get caught on branches if using the pack for hunting or on less maintained trails. The down side is you can't see what's inside the pocket and the mesh is great for drying wet gear.
Doesn't adds to pack price.
Double pull compression straps
Designed to hold skis tight and stop them moving around. The straps can still be used as a normal compression strap or slide the ski into the loop to make even more secure.
Adds $15 to pack price.
Top compression straps down the side
The rolltop on the standard pack clips back on itself like a drybag. But the top compression strap clips to the rolltop and compress the pack from the top. Good for larger volume packs that might not be full most of the time. Can get in the way if attaching skis to the side of the pack.
Adds $20 to the pack price.