If there are any records or muster lists for them I suspect they will either be at the National Archives of Scotland or in a private collection.
The Scottish Military History Society web site had a few lines of description for The Frazer Fencibles 1794-1802 linked from the old regiments.org web site, that I’ve reproduced below, but the url is no nonger available. I’ve searched for new web site, but couldn’t locate it, so assume like the regiments.org that is now only available from the web archive, it has also expired.
My search through up a web site with a main title “Scottish Military History web site-Introduction” and a URL ending dot org dot uk – although the first page looks ok many of it’s menu pages appear to be have been hijacked and some have malicious software embedded. There are other web sites with similar URL’s but ending dot co dot uk that appear safe, and there are others that may be able to help, but before you access them ensure you have good anti virus software on your pc, ipad or iphone.
The Fraser Fencibles 1794-1802
Raised in 1794 by James Fraser of Belladrum.
Embodied in 1795.
Dressed in Highland uniform, with black facings.
Strength over 350 men; of whom 30 were Lowlanders, and 18 English and Irish (all old soldiers) were enlisted by some officers to make up their complement. The rest were Highlanders, 300 of whom bore the name of Fraser.
It served throughout the rebellion in Ireland in the late 1790's.
Disbanded in 1802