While the Sarna list is not comprehensive, to say not even remotely so would be a mistake. Using the MUL and filtering for FRR along the appropriate timelines returns 28 hits vs Sarna's 21. Now, there are a variety of factors that make even that off, the most glaring being that Draconis Combine and Lyran mechs are relatively common in FRR space due to the time spent under their rule/at war with them, so any list really should include a subset of each sides forces. The Sarna list is a quick and easy listing of mechs that saw the most service in FRR forces.
That being said...I like the Battlemaster...but the Wolfhound is a standby favorite, more so if we get to melee.
That is only if you ignore the IS general list which consists of designs that are going to be every bit as common and brings the total to 58 IS tech designs in just the late Succession Wars and Clan Invasion. It also shows a number of mainstay designs like the Archer variant built in the FRR which are totally missing from the Sarna list.