A no-forma build for [Titania], viable for both the Index and for killing what you have to. Plenty of room to experiment, I'll provide substitutions and details below. Diwata Prime build is on the way!

Dex Pixia Prime:
0-1 Forma: https://overframe.gg/build/263627/

Diwata Prime:
0 Forma: https://overframe.gg/build/263662/

Index Use
[Titania] is just about the best DPS frame to bring to the index, competing primarily with Mesa (note to self, make a Mesa Prime build) for the top kill score - if that even matters to you. In her razorwing form, her [Dex Pixia Prime] pistols will slaughter brokers with a respectable status chance and massive fire rate, which only goes up with this mod setup. On top of that, she's really, really hard to hit when she's moving around in razorwing form, boasting a nice 50% evasion stat on top of numerous modifiers, such as Dust and [Agility Drift] (for those who use it). Best of all, the energy drops in the index allow [Titania] to keep her razorwing form up indefinitely, provided that you're alright at routing and have some efficiency investment. The only real dangers to her are staying still long enough to get booped by bullets or flying too fast into out-of-bounds.

General Use
I've brought Titania out of the Index from time to time to go kill other folks - her performance is stellar on open-world bounties such as those on the Plains of Eidolon. She gets much of the perks that she sees in the index, but keeping her form up is less reliable only because of the finite energy drops (Titania doesn't gain energy from E-Dash or [Energy Siphon] while her razorwing form is up, fyi).

Helminth
I like Fire Walker for [Titania] because it boosts all forms of speed by 25%, gives status immunity, and inflicts heat procs to save modding space on weapons. As long as it doesn't replace Razorwing, it doesn't matter where it goes. I put it over Tribute because it feels like an awkward ability to use and it saves me the trouble of toggling.

Strategy
1) Take flight with 4 {Razorwing}, and do everything in your power to stay in it.
2) Spam 1 {Spellbind} three times, either holding the cast or tapping on enemies (yes, it works on brokers) and 2 {Fire Walker} once to get a massive 284 / 309 % boost to flight boost speed and fire rate / attack speed.
3) Zip around enemies to spread your status-curing fire and heat procs (no need to put heat on Titania's exalted weapons), then smack them as you see fit.
4) ???
5) Profit.

Mod Choice

Growing Power (Aura) - [Pistol Amp], although a solid choice, is a little bit limited for this [Titania]'s kit. By using her weapons to splatter status, she gets an extra 25% bonus to the fire rate on Razorwing Blitz on top of the extra damage to her Dex Pixia Prime. It's a double dip!

Ironclad Flight (Exilus) - A good majority of the unique warframe exilus abilties aren't very nice, removing gimmicks for lackluster bonuses. For Titania, this is not the case. If you use Ironclad Flight over Aviator, you are no longer force-picked as a point [Carrier] and can do a much better job of keeping your energy up. You'll probably still pick up one or two points on accident, but at least [Rhino] won't want to swat your miserable arse out of the sky. Plus, 40% damage reduction for doing little more than staying in the sky is a no-brainer.

Razorwing Blitz - [Titania] doesn't need the extra flight speed, but dollars to donuts, the fire rate is wild! You'll empty your clip quicker than you can say, "gee Blackmist really loves his fire rate," and there is negligible recoil on the [Dex Pixia] Prime. This mod alone is probably what lets me (and hopefully you) run so many rounds of the Index with her.

Duration Mods - Even with her standard kit, the buffs from [Titania] last for quite awhile, so investment is something of a wild card. I wouldn't suggest falling below 100% duration as her Razorwing energy drain scales slightly with it and [Razorwing Blitz] has a refreshable duration of 8 seconds. Likewise, since you maintain [Razorwing Blitz] by recasting abilities, going overboard with it is not a great idea either. You could just pop on Narrow Minded and call it a day. I could care less.

Range Mods - Nope.avi

Efficiency Mods - I hear from "veterans" that efficiency is nothing more than quality-of-life and that there's things like E-Dash and energy pizzas to keep energy up, to which I reply, "nOt iN tHe InDeX!" [Titania]'s energy drain per second from Razorwing is mitigated best by efficiency investment, and some players have standards for energy management. That said, I can live with 2 energy drained per second. This build has a drain per second of 1.94. I will admit however that you don't need both [Streamline] AND [Fleeting Expertise] if you are not running [Blind Rage]. [Titania] gets a minimum drain of 1.25 energy per second at 190% efficiency and 40% duration or at 175% efficiency and 100% duration.

Strength Mods - Each percent of strength put into [Titania] is a percent of extra benefit from [Razorwing Blitz] and her exalted weapons. More is better; you're the DPS after all. [Intensify] is reliable, and I recommend at least one more strength mod. Transient Fortitude and Blind Rage both offer impressive bonuses but use them at your own volition - [Titania]'s energy drain per second from razorwing can be a bit unforgiving, so you may want to keep an eye on efficiency first, and duration second. You can still avoid a forma if you use both, drop Intensify, and use plain Continuity, your call.

Arcanes - Arcanes are a free pick, I can't tell you how to play your game. But since you've read all the way here and I somehow still have your attention, I'll say that pistol-related arcanes are a good way to go. Precision and Velocity will ramp up [Titania]'s damage output very nicely. But considering that the build has [Razorwing Blitz], some decent substitutes for Velocity are Pistoleer, Avenger, or Energize.

All done. Thanks for reading through, and I hope the build is helpful. Go make me proud and get that John Prodman poster!