20 cards where the card types include “sliver” and (the card is available on Paper) and the toughness = 3

Battle Sliver (Magic 2014 #128)
Brood Sliver (Commander Masters #887)
Capricious Sliver (Commander Masters #734)
Constricting Sliver (Commander Masters #818)
Dementia Sliver (Time Spiral #236)
Essence Sliver (Time Spiral Timeshifted #8)
First Sliver's Chosen (Modern Horizons #9)
Fury Sliver (Time Spiral Remastered #164)
Lymph Sliver (Time Spiral Remastered #25)
Magma Sliver (Legions #107)
Megantic Sliver (Commander Masters #901)
Pulmonic Sliver (Time Spiral Remastered #34)
Regal Sliver (Commander Masters #724)
Spitting Sliver (Planar Chaos #80)
Synapse Sliver (Commander Masters #857)
Synchronous Sliver (Planar Chaos #48)
Taunting Sliver (Commander Masters #727)
Toxin Sliver (Legions #84)
Vampiric Sliver (Time Spiral #140)
Venser's Sliver (Time Spiral #267)

It is the moment of discovery, the triumph of the mind, and the end of these results.