Since I've spent over 30% of my time in Warframe with [Limbo] (counting both [Limbo] and [Limbo Prime]), I thought it would be a great idea to share the builds I've created and curated for him during that time, starting with this general use build.

This build is incredibly versatile due to how much you can swap out to account for different situations.
The mod setup I have here is the one I use most often. It works well on any mission type where objectives are mixed or less Defense focused (with Interception as an exception, where the range will do a great job covering whatever point you want to lock down). This makes it my go-to build for using [Limbo] in the Plains of Eidolon, Orb Vallis, and Cambion Drift.
I also pick it for Exterminate and Capture, but mostly just when I feel like playing [Limbo] instead of using a proper DPS frame. That's not to say [Limbo] won't be a nice bonus during those missions, and this build is an amazing choice to solo Steel Path missions for the slow and steady kind of player.
The strategy mostly narrows down to keeping Stasis on most of the time, dropping Cataclysms on groups of enemies, and getting energy back from kills in the Cataclysm to fuel more ability casts. This playstyle provides a very effective use of [Limbo]'s abilities, without annoying allies to no end by constantly Banishing enemies for your own selfish gains.

A quick rundown of what mods you might consider swapping for different situations.

• Aura: [Power Donation] is a good pick for most [Limbo] players, but those looking into taking advantage of Helminth, like myself, may opt out for another mod (Energy Siphon being my personal choice).
• Exilus: [Limbo]'s unmodded casting animations are cripplingly long. [Natural Talent] alone fixes the problem, and [Speed Drift] provides a lovely extra bonus. The only mod I'd consider swapping it for would be Cunning Drift, but I don't think the added range is needed on this build.
• Augur Reach: If a smaller bubble with less shrink will fit the mission better, Augur Message is the go-to mod. This may be useful on Excavation nodes, though for those, I personally opt for a max duration build with [Stretch] added to counteract [Narrow Minded], which covers the Excavator completely for most of Cataclysm's lifespan. I would recommend the reduced range more for public Survival missions, since it lets you focus on controlling a specific choke point on the map, without catching random enemies you aren't looking at.
• [Streamline]: Another mod that can be swapped out for [Augur Message]. While the energy cost may seem expensive, the amount of energy Limbo can gain in a short time is absurd, and tends to balance out with the cost of Cataclysm.
• [Vitality]: If you plan on spending the entire game inside the Rift, you could opt out of this mod for something else like [Augur Message], but this can make [Limbo] a bit less versatile, and even somewhat boring. Nullifiers are pretty much an absolute death sentence on higher levels if you take this mod off.
• [Natural Talent]: I... hey, friend, it's your funeral I guess. In all seriousness, as I mentioned before, Limbo's casting animations are painfully long. I wouldn't recommend removing this one.
• Primed Flow: Substitute regular flow if you don't have the primed version. I really wouldn't recommend dropping this one.
• [Primed Continuity]: Same thing as Primed Flow. If you don't have the primed version, use the regular one, and you probably don't want to take this off.
• [Constitution]: You can use [Augur Message] if you don't have this mod yet, but you should definitely get it by doing some Nightmare Missions when you have the chance.

Concerning the arcanes.
Energize is just a nice bonus (I actually still have a Rank 0 due to a lack of time and bad luck during Tridolons).
[Limbo] really doesn't need it, because he already gets passive energy [Regen] in the Rift, which can be combined with the Zenurik bubble for a whole 7 energy a second, which stacks on top of the ten energy per kill on enemies in the Rift.
However, I've become practically dependant on Arcane Guardian. It opens up the world of open combat by making up for Limbo's otherwise paper-thin body, which will help you greatly against the dreaded Nullifiers that are even more of a pain for [Limbo] than other frames. The same goes for other frames that can't take a lot of hits like [Banshee], so if you're looking to grind for or purchase at least one Rank 5 Arcane, I would highly recommend going for [Guardian].