Krispy Kreme is the standard and best bnb. You should also have an air to air combo, there are lots of variants to choose from.
Iron Man cannot combo off a midscreen ground throw. He can only combo off a throw in the corner (in which case you can link c.L after a throw for better scaling), or close enough to the corner where you can dash in and do L Smart Bombs, c.M, s.H S etc.
Off any height air throw, ADDF towards the opponent and do L Smart Bombs, c.M, s.H S whatever. If you see that the opponent is too far away to connect after L SB, dash in after L SB and connect c.M, s.H similar to the way you do the midscreen Repulsor combo after you hit them with L SB. You can also do air Smart Bombs L and do ADF j.uH or something after a normal jump height throw but I think the other combo is more consistent and less height dependent since it works from both normal and super jump height.
Corner combo variants and corner throw where I can link c.L I just do the KK because I run Iron Man anchor without assist extensions because Iām stupid. If you want something more damaging, for both corner combos and corner throw combos, check Duck Strongās YouTube channel. Iron Man struggles to break the 800k damage barrier by himself, but its really easy to work assist extensions into his combos. Getting big damage with Iron Man involves using assist extensions to do as many Repulsor Blast loops as possible before you have to Spread and do H Smart Bombs into a Hyper.
For TACs, there is really no reason to not learn his infinites because they are so good, but in the mean time if you want something a bit more standard Danke came up with some good stuff that just involves juggling the opponent on top of a Repulsor Blast, cancelling into Spread and either doing Proton Cannon or Iron Avenger.
Last but not least the Repulsor Blast xx Spread combo, let RB hit four times, spread, dash and do L Smart Bombs as late as possible, dash again and do c.M, s.H, S, air series, spike, OTG H Smart Bombs whatever. Decent damage and if you play Iron Man with assists you may be able to do something better here, but that simple combo is universal against the whole cast off any strength RB and any height as long as you let RB hit the correct amount of times*.
*I think, if Iām wrong someone please correct me.