What’s the best full-text search app for Mac, preferably one that supports wildcards and quotes and filetypes – and that does its own indexing?
I find Spotlight to be… spotty. Its indexing is mediocre and seems to miss a lot, even when I rebuild the index.
EDIT: I guess I’m also interested in really good search apps that use the Spotlight index… I would be willing to try them, anyway.
There are some search apps out there but Foxtrot Search is only one that I am aware of that does its own indexing. Its quite expensive and probably more than most people need. I use Foxtrot Search but also do not have too many problems with Spotlight. If you find apps with similar functionality to Foxtrot Search let us know.
If you are up for some programming then the Lucene search engine from Apache https://lucene.apache.org/ has all that and more. The Solr extension https://solr.apache.org/ would be worth investigating.
Out of the box Lucene/Solr use a server model but there are some corpus linguistics programs buillt on Lucene that do everying locally. Programming that and your personalised GUI will give you what you want. And, of course, being open source the only cost is your time to do the coding.
Foxtrot for own index
HoudahSpot for spotlight-based search.
If you’re going to go this far, try ripgrep
Just a binary that you run in the terminal as opposed to working around a server/client model
HoudahSpot is already mentioned above. I find it more than meets my needs. There are two things that may help @brainstormer in specific: the free trial you can download, and the PDF manual. The manual goes into decent depth about how it specifically works with Spotlight. Here’s the link: https://www.houdah.com/houdahSpot/help/HoudahSpot%20Help%20EN.pdf
Not sure if this meets your criteria, but I like EasyFind by the makers of DevonThink. It’s free. They claim it doesn’t require indexing.
Thanks for sharing this, I’ve downloaded it and for my use is so much better than Houdahspot.
Saved me plenty of time already 
At £35 for the personal search I don’t feel it’s that expensive - especially when compared to the price of some calendar subscriptions 
This is a good recommendation and I really like Foxtrot on my Mac. Comes in handy from time to time and seems like a “lighter” implementation than some of the bigger pieces of software out there.
That’s an intersting tool but surely fails on the criteria of “does its own indexing”? All grep work-a-like tools rescan files each time where as Spotlight (for all its failings) and a Lucene/Solr or similar approach builds its own indices once and then uses those; Lucene/Solr can cope with incorpating new material.
Plus the kicker that grep work-a-like tools are usually run in a Terminal session whereas Spoltlight, Lucene, or others have a GUI interface.
Seconding this. EasyFind is and does exactly what it says on the tin. I’m fairly certain it doesn’t index anything though—it’s fast, but not “has an index” fast.
Howard Oakley weighs in:
Spotlight on search: Better and different, 3rd party apps – The Eclectic Light Company
All Spotlight searches were essentially instantaneous, but searching ~/Documents in EasyFind took 21 seconds …
The only answer is to have all of these products: I now use HoudahSpot as my primary search app, and wouldn’t be without it, but know that being able to fall back on Find Any File and EasyFind is essential.
@those who recommend HoudahSpot:
If really Spotlights indexing is faulty (which I could not agree to from my experience) how should HoudahSpot be any better, if it is using the exact same index?
And even worse, how could it be better than Spotlight, if it even could not access the results of the spotlight CoreIndex?
Spotlight search works fine for me (and apparently for others, too) but the front end that HoudahSpot provides to Spotlight, its app interface, offers many options and is a joy to use.
Welcome to the forum. 
Thanks! Looking forward to learning a bunch and contributing what I can.
Sure. I didn’t interpret the question as requiring an index though.