Flex slots
Primed smite grineer - flexible for Gladiator Might
Molt Impact - flexible for Gladiator Might
Berserker Fury - flexible for [Primed Fury]
[Discipline's Merit] can be used for Tennokai heavy slams.

[Condition Overload] does NOT affect [Desert Wind] waves so do not equip this unless you plan on doing direct hits e.g. on demolysts or with grouping.

Other factions
Corpus - Swap [Vicious Frost] for [Virulent Scourge] and [Molten Impact] for [Gladiator Might] to make pure toxin to bypass shields (may need Umbra forma to fit at max mod ranks). Swap Smite Grineer for Corpus.

Infested Deimos - Swap [Vicious Frost] for [Voltaic Strike] to make Corrosive + Heat and Primed Smite Grineer for infested or gladiator might.

Stat Stick
Praedos Gladiator Stick: https://overframe.gg/build/330674/ (gives movement/parkour speed and requires you to spend primary/secondary ammo occasionally to maintain combo). This pairs well with weapons that either reload passively (Tenet Envoy/Felarx) or do not require reload (Epitaph).

Gunblade Vastilok Gladiator Stick: https://overframe.gg/build/388013/ (requires you to exit serene storm occasionally to maintain combo)