I've been investing for 10 years (4 on my own, 6 at a fund) and I've tried virtually every stock research tool under the sun. In my first two years at the fund, a big chunk of my job was dedicated to just finding and vetting software/data providers that could help the research team.

I've received literally hundreds of demos from vendors over the years so I feel uniquely qualified to provide this list:

Individuals/Small Funds:

Fiscal.ai (Free Tier or $39/mo): This is the most complete data terminal for global stocks at a reasonable price point. Having been around the block when it comes to data terminals, I can say that without the slightest hesitation. They're much better than competitors when it comes to UI/UX, but more importantly, the breadth and depth of their data is just as powerful as the institutional tools. Not to mention, they're the only one that has Segment & KPI data.

Quartr (Free Tier or ~$400/mo): The best earnings call and event transcript library. Even though transcripts are sort of a commodity, Quartr's mobile/tablet UX makes it the best for reading transcripts when you're away from your desktop.

Morningstar ($35/mo): Morningstar's equity research coverage is pretty top-notch for its price point. Their initiation reports and quarterly coverage are typically enough to get you up to speed on a company's current situation/narrative. Only downside is their coverage is limited to less than 2k global companies. I get all their reports included through my Fiscal.ai sub as well.

Finviz (Free Insider Trades Tracker): I use Finviz exclusively for their insider transactions tracker. It's the most up to date tracker I've found. Once a week I just scan for latest insider buys and see if anything piques my interest.

SeekingAlpha/Motley Fool/GuruFocus (free articles): The quality can be spotty on these ones, but every once in a while you'll find a bright, young analyst that actually does solid research for these sites. Can be nice if you're on a low budget and trying to get up to speed on ideas.

Institutions:

Visible Alpha ($20k/yr): This was basically started as a consortium. It was a "you give, you get" model that allowed sell-side analysts to upload their full Excel models and get access to Visible Alpha's repository of models in exchange. To this day, they are the only provider I know of that provides consensus estimates for company-specific KPIs.

Tegus/Alphasense ($15k/yr): Expert networks are a nice way to get deep knowledge on a company. If you're an analyst at a big fund, it can definitely help you gain some unique insights compared to your peers. If you can afford to pay for one, it's worth having access to it. However, I encourage people not to place too much value on these transcripts. I've seen numerous instances where the "expert" has a major bias (positive or negative) towards a specific company that clouds their judgement.

Bloomberg ($30k/yr): I know most people reading this probably don't have $30k to throw at a research terminal each year, but I've gotta mention them. If you're running an institution that needs a full end-to-end tool, there's still nothing that comes close to matching a Bloomberg terminal. From data to news to research to messaging to trade execution, it truly is the gold standard for a reason.

Software that's not worth the cost:

Factset & CapIQ (both ~$15k/yr): Both of these tools are dinosaurs and you can feel it the moment you use their software. Don't get me wrong, they've got some powerful features, but you can get 95% of the functionality for 1/10th of the cost elsewhere.

Also, for those unfamiliar with the financial data space, the way these guys aggregate financial data is they have 20,000+ employees in Asia (primarily India and The Philippines) that manually collect the data as it comes in. So say a company reports quarterly earnings, one of those employees in India will go through the 10-Q and manually enter a bunch of numbers that he's assigned to look for. Those numbers will then get reviewed, cleaned, standardized, and published. It's such an outdated process, and that's why it often takes Factset and CapIQ days to display a company's latest financials.