This is a sub-page of Crash Bandicoot 4: It's About Time.
Relics#
Although they only appear as 2D models in-game, there are also fully 3D models for each type of relic.
N. Sanely Perfect Relics#

Models and animations exist for three variations of the N. Sanely Perfect Relics. In the final game, only one variation of this item exists. It appears this item was originally going to feature some sort of ranking system, similar to the Time Relics and Flashback Relics.
(Source: The Wumpa Gem)
Time Relics#
Flashback Relics#
These don't have backs, so they were probably intended to only be seen from the front.
Placeholder Models#
Pixelmon Cortex#
A low poly placeholder for Cortex.
N. Sane Trilogy Models#

Models of Crash and Dingodile from N. Sane Trilogy, very likely placeholders.
The Elementals#

Crates featuring Aku Aku's Skylanders design, along with fanart of Uka Uka (by DeviantArt user RedandBluereviews, who has since deactivated their account) and the Elementals from Crash Bandicoot: The Wrath of Cortex minus Lo-Lo (by DeviantArt user Lurking-Leanne) over a strangely modified rip of the original games' box texture. These may have been used to trigger the Quantum Masks during development.
On That Grind#

Placeholder meshes to build the rail sections and to indicate where the player should jump.
Boss Level Icon#
Early icon on the map for the bosses.
Buddy Collectables#
An early prototyped collectable from the games prototyping phase containing 2 flattened dummy models of dingodile.
StoneRoller (L008)#
Placeholder Model for the Stone Roller found throughout the game. The name features the level id L008 and is found in the level folder for L008. The .umap for this level doesn't exist in the files.
Bony Hawk's Pro Skater#

































Placeholder meshes for level design. The widths are measured with crates!