Instrumental metal bands off the top of my head, along with more or less what they sound like (IMO) -
Blotted Science - Basically... very heavy, very technical, very fast, non-stop riffs flying around for an hour without any sort of real break.
Exivious - Two guys from Cynic, a guy from Textures, and some other guy decided to make an album. It mostly sounds like a Cynic record, and in a lot of ways is more interesting than Traced in Air.
Behold... the Arctopus - Blazing technical metal with a heavy focus on non-repetition and with Warr guitar as the central instrument. Both of their EP's are amazing; their first LP, however, was somewhat disappointing and I wouldn't particularly recommend it.
Continuo Renacer - Cynic/Atheist worship.
Canvas Solaris - Kinda masturbatory and meandering. Reminds heavily of bands like Cynic and Alarum in some ways, not so much in others. I think a lot of their music is somewhat flat if technically impressive, but I'm just one guy and lots of people dig them.
Actual Time - Pretty much unknown band... I only know about them cause they're from my city. Lots of crunchy riffing, driving bass lines, and rhythmic stuff you'd expect from tech metal, although occasionally this doesn't sound much like metal.
Animals as Leaders - A guitarist's (Tosin Abasi) solo album, but it isn't really a shredfest or anything like that. Good amount of creativity and diversity in tone and style, cool drum tracks, and some atmospheric stuff going on here and there.
Cloudkicker - Sounds sorta like Nothing-era Meshuggah mixed with Textures. Shares similarities with Animals as Leaders.
Electrocution 250 - To quote another reviewer: Well, that's right. This is some of the sickest, most off the wall instrumental music you'll ever hear. Sure, the question of songwriting will pop up in many minds; and I'll definitely agree this is not for everyone. Of all people, fans of quirky instrumental music or guitar players should enjoy this album the most. Think the playfulness of Bumblefoot and the dazzling speed of Behold the Arctopus. Now give it a Spastic Ink spin, if you will. There you have it - Electrocution 250, a most impressive instrumental trio consisting of GIT-schooled Todd Duane on guitars and bass, Lale Larson on keyboards and piano, and last but not the least Peter Wildoer on drums, who previously played on Darkane and Time Requiem albums. Songs are generally faster than lightning and leave the human mind in knots.