From Lexicanum

Basic Data		Uniform	Regiment Badge	Example Miniature
Regiment Name:	Tiger Lizards
Homeworld:	Unknown
Regiment Type:	Unknown

13th/23rd Tiger Lizards

The 13th/23rd Tiger Lizards are an Imperial Guard regiment known to have fought against the Tyranids, with the regiment's Lieutenant-Colonel Uskra commenting on their ability to attack in perfect coordination.^1-p72 They may also be a split regiment due to their naming - the 13th and 23rd being two previously separate regiments, merged into one.

17th/21st Tiger Lizards

The 17th/21st Tiger Lizards are an Imperial Guard regiment known to have existed in M30. Their presence was recorded in the Codicium Arkathalor in the campaigns in the Pandora Sector. They were recorded as one of at least two regiments made up of 'split' formations, where two wholly individual, but badly mauled, regiments were merged to produce one battle-ready regiment. The other regiment recorded was the 61st/320th Orenian.^2-p6

Sources

• ¹:Codex: Tyranids (2nd Edition)
• ²:Codex: Imperial Guard (3rd Edition, 2nd Codex)