Unstacking the Deck: Marvel Ultra Onslaught

Fleer Skybox 1996

Vital Statistics

100 cards, plus a three card promo set (featuring Heroes Reborn Captain America, Mr. Fantastic and Iron Man), a four card Autographs chase set, a three card "Mirage" chase set featuring lenticular cards, and four exclusive Overpower hero cards and nine exclusive Overpower mission cards. 

Categorically Speaking

The majority of these cards are standard hero/villain portraits, with the standard 100th card checklist, plus twelve cards smack in the middle of the set that summarize the plot of "Onslaught" (these basically functions as an additional category but are not labeled as such). 

Firsts and Other Notables

"Marvel Ultra Onslaught" functions, essentially, as a trading card set featuring the major players in the "Onslaught" crossover. Each card front image is full bleed (no borders) and enhanced with CGI coloring/effects. Card backs list the character's real name, team affiliation and power, with brief biographical information about the character written either from the perspective of Professor X or Onslaught, along with information about the artists who worked on the card. 

Unstacking the Deck: Fleer Ultra X-Men: Wolverine

Fleer 1996

Vital Statistics 

100 cards (including the checklist card), plus a nine card Holoflash foil and three card "mirage" insert sets. 

Categorically Speaking

Weapon X, Department H, Second Genesis, Japan, Allies, Madripoor, Mojoworld, Enemies, X-Men, Age of Apocalypse, Savage Beast 

Firsts and Other Notables

While not Fleer's only offering of X-Men cards this year (they also put out the higher end chromium set, as well as a set of "Onslaught"-specific cards), this is the set which is the most direct sequel to the previous two years' "Fleer Ultra X-Men" sets. It is, however (in perhaps the most 90s thing ever) focused on Wolverine, rather than the full X-Men team/universe. 

As such, aside from the more standard "allies" and "enemies" categories, most of the categories represent a specific time or setting from Wolverine's history, with each nine card subset featuring characters culled from that era/setting alongside the relevant Wolverine card (so the Department H cards feature Wolverine in his first costume along with cards for Alpha Flight characters, the Madripoor subset his Patch outfit and cards for Tyger Tiger, Roughhouse, etc.). 

Unstacking the Deck: Fleer Ultra X-Men Chromium

Fleer 1995

Vital Statistics 
100 cards (including the checklist card) plus a twenty card "Alternate X" chase set, a nine card "Lethal Weapons" chase set, and a gold signature parallel set.

Categorically Speaking
Teams/Superheroes/Supervillains, Wolverine Timeline, Haunted Mansion

Firsts and Other Notables
The cards in this set are all "chromium", which as far as I can tell, means they have a slicker finish and a more embossed, nearly-3D look to the art (it's the same gimmick that was applied to the covers of Generation X #1, X-Men: Alpha and X-Men: Omega). All of the card art is fully painted and from either Andy Kubert (the regular X-Men artist), his brother Adam (the artist on Wolverine) or their father Joe (a classic artist of the Silver Age who founded a school for comic book art).