Yeah, discord tamer is useful for spawns, but really isn't that good for soloing. My first though was necro-peacer as well.
I solo a lot of spawns, and I like to think of it as 3 distinct stages that you need to deal with. First is the tiny stuff at the start, second is the big stuff in levels 3 & 4 and third is the big boss at the end. Let's look at each step.
First step is the little stuff - be it slimes, scorpions, lizard men, whatever. Obviously, this stuff isn't tough to kill, but you need to kill a lot of it to move the spawn and if you're working solo, it can be a challenge killing the stuff fast enough. The two templates best suited for this are sampire & necro mage (or some template with wither). Bard skills are not suited to fighting little stuff - the cool-down timer pretty much makes provoke or discord a waste against little spawn creatures. The only useful bard skill for low-level spawn might be peace in situations where there are spellcasters (imps, undead) that make withering them a pain; so we're talking necro-peace template again.
Second step is the bigger spawn creatures. Provoke is perfect skill for pretty much every spawn at this stage (maybe not bedlam or primeval lich because they have creatures that are immune to provoke); but dragons, teretan avengers, demons, etc. are all easy prey for Provoke. In conjunction with a skill that deals out damage (magery, archery, necro, perhaps spellweaving or mysticsm or even melee), a top-notch provoker is able to move the level 3 & 4 of any spawn solo. A sampire can also accomplish this at most spawns, and an ABC archer can definitely do so by himself as can a necro peacer.
Third step is the boss. This is where it gets tricky for the bard because you need to do a lot of damage to one creature. Discord is nice but doesn't do any damage on its own, and provoke & peace are generally not a big help on their own either. In some cases, such as the reptile & arachnid spawns, you can plan strategically and leave enough dragons, poison elementals & terethan avengers around to provoke onto the boss to make it worthwhile. But in all cases, you need to have some other skill besides bard to deal out the actual damage to the boss. Archery, magery, necro in conjunction with bard skills could get the job done in some cases. ABC archer is definitely the best for this task, necro can get the job done. A discord tamer would work in some situations.
So, going back to the original question. If you want one template that can accomplish all three tasks and also includes bard skills, a necro peacer perhaps with provoke would be able to do it. If you're willing to switch in the middle. I'd highly recommend a necro mage or sampire for early spawn, and an ABC archer for later spawn. You can solo any of the rotating spawns with these. I'm a bard at heart, but these skills are a better match.