I just hit L10 with Ada, she’s lots of fun to play on deity.
Here is my favorite combo, I would love to hear yours!
tldr: Han, Mongolia, Great Britain
For mementos I’ll start with +1 science and culture on specialists. Combined with Ada’s science and culture mastery bonuses, these mementos massively accelerate her advancement in the last two ages.
Han is my favorite starting civ for Ada. I’m honestly surprised this civ isn’t recommended for her.
The Chu-Ko-Nu is an excellent city defender. This helps Ada survive early in the game since she gets no starting military bonus — she has to earn it through science and culture. And in mid/late antiquity, a swarm of maxed-out Chu-Ko-Nus can be quite formidable as an invading army behind a few chariots.
You can also earn two diplomatic leader attribute points as Han if you prioritize recruiting city states. This sets you up with a 50% reduction in city state acquisition, which is a major boon at the start of the exploration and modern ages.
Final note for antiquity — the economic golden age is essential. By keeping all your cities, you start the next age with massive momentum from your memento-buffed specialists. I try to start exploration age with 5 to 7 cities.
Mongolia may seem like a counter-intuitive choice for Ada, but hear me out. (Bonus: simply imagining Ada as a nerdy Daenerys Targerian makes this combo fun to play. 🤓)
First, all of your Cho-Ko-Nus become Keshigs, another powerful archery unit. And with your cities already established and cranking out science and culture, you can immediately prioritize buying a few cogs and settlers to quickly find and establish premium foreign land settlements. This is essential as the economic golden age once again lets you keep all your cities going into the modern age.
Ada’s science and culture combined with the Mongolian military bonuses make this combination an unstoppable military force in the second half of the Exploration age. And the Mongolians keep getting Noyan commanders as free bonuses. All of these expensive commanders are preserved going into the modern age.
Finally, for religion I try to get the +2 relic bonus for converting a city with 3 or more specialists. Since most of Ada’s settlements are already cities, this makes relics a trivial afterthought.
Great Britain is an easy choice for Ada in the modern age. By preserving all your cities, you bypass GB’s town upgrade penalty and massively benefit from GBs production bonuses.
The science and culture mastery bonuses are significant in the modern age, so Ada’s special abilities really start to shine.
For a cultural victory, just buy two Antiquarian units as soon as possible and have at it. It helps if you thoroughly explored foreign lands in the prior age.
For a science victory, just keep cranking out specialists and science buildings in your established cities, with a secondary focus on culture and production buildings. I generally research most of the early science tree up to flight, then heavily prioritize the science victory conditions.
Also, GB’s Revenge class battleships are formidable and the Battersea wonder makes them absurdly cheap to crank out en masse.
Other victories are also reasonably straightforward with Ada and GB. That said, science and culture victories are so easy with this combo that I rarely see the need. I’ll generally pursue both culture and science victories in parallel and decide which one to finish as the age progresses.