At rank ~1100 now
Flankers: Tbirds, Fieldmasters, Sunset Sages, Ravagers
Escorts: Anything mobile or anything that buffs you
Attackers: Anything that can soak up other attackers/escorts really, not even sure this slot REALLY works
Defenders: Caster types and Blade Dancers if you can spare them. Multi Proj Tidecallers are really good
The fieldmaster thing for flanker is best paired in the same lane with a Tbird because they can teleport around their walls or a sunset sage/tidecaller because they can range a totem beyond the fence. They do cockblock your own teammates, but not NEARLY as bad as they cockblock the opponents. For 600 they're a really good unit. Beware enemy Blade Dancers and Spear Fishers apparently walk through their fences.
Sunset Sages are maybe tied with the best flanker. They're slow, but they have a blink skill to avoid attackers. They freeze the enemy whose totem they're banishing. They have OMEGA range on their totem banish which I believe is unique among all of the units. Even tidecallers/sages have to get close to hand-channel. Throw on a Massive Chisel, Proxy Shield, or Just 100% hp and they're fuckin'.
Thunderbirds are best paired with the bauble that heals their hp while banishing, birthing spoon, 50% insta revive, 50/50 block item, prox shield, or 100% health. They're VERY squishy, but they're hard to nail down. The low health leads to the REAL problem higher up:
Death's Guides. These guys have a chaos aura around their totem. Why is this a problem? Because none of your units have any chaos resist. So it can literally be ONE Death's Guide totem versus 4 flankers and it may take them all 3 lives EACH to take that down. And UNFORTUNATELY it is usually accompanied by a Mystic who HEALS the totems making it impossible for anyone outside of a Sunset Sage who can out range it to take it down. I have 75% chaos resist and even with my full hp every 4 seconds bullshit I still have to use a pot once or twice during a single channel to take it down.
Titanic Shells are still a problem. One turtle can, as of last night, protect 7, SEVEN, fucking totems at once. And the real problem is your flankers won't attack it. They attack totems, not mobs so even if it's the ONLY monster on that side of the field, they will just mill around aimlessly or get goalied by attackers. I sat dead for 20 minutes last night hoping, HOPING, that of my 4 flankers and 4 attackers left SOME ONE would walk across the field to kill the half dead turtle. Never happened. The other teams escorts/attackers slowly wittled down everything one by one because I even had defenders. Statistically I should have won, but the AI is in a port state versus some elite units. Same goes with Death's Guides. In the right position they'll consume your flankers over and over again and if paired with a mystic you're flankers will never kill a single totem without you.