Hello everyone! I can recommend a free plugin type arpeggiator with a random function? thanks

My Trashathon has 3 arps with 1-4 octaves, and you can set the righthand sides to random, which will do randomly which octave gets played.

-Windows 32bit plugin

Check your DAW.
I know Logic has that in it's Arpeggiator

Arp!0 does nice random, you can even set for each part like for example transpose, length, gate, voices etc etc.

Thank you for answer! I would be interested arp!0 but I can not get it to work in reaper! I'm reading how to do it but to no avail.
how do you?

In Reaper's menu, click:
Options - Show REAPER resource path in explorer/finder.
A Windows explorer window will be shown. Put the Arp!0 files in the folder called Effects there. (the midi_arpbangzero file has no extension, that is normal, don't worry about it)

Now restart Reaper and just load the arp as a normal plugin on any track.

The random features are in the settings page. To open the settings page, click the word [arp!0] in the top right of the main page.

Not precisely an arpeggiator, more of a phrase sampler, but you might be interested in Chroma for Reaktor:

http://www.reaktortips.com/2012/12/chroma-and-gris-gris-sequenced-monster.html

It allows you to quickly enter semi-random phrases and warp them on the fly while restricting the notes to a scale. An upcoming version will be midi-triggered to allow the stored phrase to be transposed by incoming MIDI pitches.

Thanks for this, might note that you need the full Reaktor ($399) not Reaktor Player (FREE) to run this Chroma.

Yeah, I highlighted that in orange down near the buy button. I think I've only had one person buy one of my Reaktor ensembles without realizing it wouldn't run in the free player, and refunded the purchase when they asked.