Hadn’t forgotten about your Duncan question @Blummers32
Outside of Richmond’s small (predominantly pressure built) forward line, the other big chance in the past 2 seasons has been set-ups for bounces - basically it seems that they like the maximum amount of people moving through the square possible. Almost every team now starts bounces with 5 in the forward line and 7 in the backline - seeing the extra has been taken from the forwards, seeing the extra comes from the forward line, most sides rotate their small forwards through the role: sprint through the contest, hopefully impact it in some way, then continue sprinting until they reach their normal spot in the structure - we seem to prefer starting Walla or Fantasia there. That is the general structure but in particular Goodwin, Pyke and Clarkson have used convoluted structures in the past, with Goodwin & Pyke continuing this season.
Not every team operates this way though
Geelong: Plays an extra mid in the role in Duncan who then becomes an extra mid in general play. They briefly experimented with Kelly in the role as well.
Port: Westhoff did it a fair bit last season. This season they mainly use Rockliff (sometimes Ebert) in the role who also becomes a 6th mid in general play.
Fremantle & North: Briefly trialled Lachie Neale & Jed Anderson in the Duncan version of the role mid-season before reverting to normal. Ross has run with the extra forward starting as a 3rd wing rather than back at times as well - something he loved doing at home games last season.
Collingwood: Rotated Treloar & Sidebottom through there who then became 6th mids in general play. Post Treloar injury, they seem to be sticking to normal structures. Crisp typically mans the opposing forward who is tasked with running into the square and runs in with him, then he resumes his backline duties - should’ve been clearer in the explanation @Vandrs, rather than appearing to dismiss it, as it was partially correct.
Hawthorn: One of the biggest proponents of experimental set-ups - last season one of the keys to their late season success was by starting only 3 forwards at bounces, both their wings started in the backline with the extra forward and the 2 other forwards started on the wings, so they could temporarily mind the opposing teams wings. Every team let them get away with it, until Beveridge in Rd 23, who pushed his wings forward to cover their wings at bounces - starting with 8 forwards and no wings. This season we haven’t had anything that extreme but O’Meara had been used in the Duncan version of the role until 4-6 weeks ago, and Isaac Smith has also been used in the Duncan role when they want to give Morrison a game on the wing.
Adelaide: Last season, Pyke started his wingers 20m closer to their backline to help in the event of a quick clearance. This season they have 2 completely different structures: a normal structure where Betts or Gallucci starts off the back of the square and Seedsman & Atkins start normally on the wing. Or structure 2 where they start with 4 forwards, have Atkins & Seedsman both start off the back of the square and the 2 forwards (typically Lynch and a small) mind their opponents for bounces - Lynch sprints towards the forward line and the other runs into the bounce to provide another option. Atkins & Seedsman resume their wing roles at the earliest stoppage - structure-wise Pyke seems to be fine with their opponents being free until then.
Melbourne: Not sure whether Goodwin was the first to start the craze, but he was probably the first to start using mids in the role, as he was starting his wings (Lewis & Tyson) off the back of the square before Clarkson & Pyke. This season they typically have 2 structures (early doors they also used last seasons structure): normal with the back of the square being one of their small forwards or convoluted - the far winger is an actual wing, the camera side winger is the 6th forward with Tyson or Jones starting off the back of the square. The place-holder wing is instructed to man Tyson/Jones’s opponent until Tyson or Jones gesture (raised hand) to Spargo/ANB etc that they’re right to resume their wing duties and manning that opponent - the handover is made, then the forward resumes their forward role. Not sure what happened in the Geelong game, but it definitely broke down as at times - no handover was made despite stoppages so Tyson instead became a 6th mid, at others when Tyson was resting, JKH was in the role and played it as a normal forward would - sprinting through the contest to the forward line. They’ve resumed normal structures since the loss, so possibly they identified something amiss in the review (or realised how convoluted it was).