It is possible to get a lot of speed without item sliding, using certain enemies.
Stun a Magtail and wait until it unmorphs. Stand close to it. As soon as it unmorphs you will take damage, and during your damage invulnerability, pick him up and you will slide at high speed.
To perform a bokoblin slide, you must first disarm a bokoblin. Wait until the bokoblin runs to get his weapon back and stand next to him. The bokoblin will usually perform a ripost attack as soon as he gets his weapon back, and that will make Link slide at high speed. Note that the furthest the bokoblin has to run to get his weapon back, the fastest your slide will be.