Sigma Posting (Follow on BS)さんのイラストまとめ

Bowsigma

Source: Bowser
Super Mario Bros. (NES) by Nintendo R&D4

Tono's Sigmas

Source: Tono's Ghosts
Ushio to Tora (SFC) by Yutaka

Master Siggins

Source: Master Higgins
Super Adventure Island (SNES) by Produce!

Pizza Sigmonster

Source: Pizza Monster
Teenage Mutant Ninja Turtles: Turtles in Time (SNES) by Konami

Sigmeck

Source: Beck
Mighty Gunvolt Burst (Switch) by Inti Creates
Sigma face edited from sprites provided by @hansungkee1 and Aburtos

Cowardly Ligma

Source: Cowardly Lion
The Wizard of Oz (SNES) by Manley & Associates

Sigmiguel and Brutusigma

Source: Miguel and Brutus
Human Killing Machine (Atari ST) by Tiertex

Sigmegazord

Source: Megazord
Mighty Morphin' Power Rangers (Genesis) by Banpresto and Nova

Dick Siggy

Source: Dick Tracy
Dick Tracy (Genesis) by Sega

Sig, Sigg and Siggy

Source: Ed, Edd and Eddy
Ed, Edd n Eddy: Jawbreakers! (GBA) by Climax Group