For me the absolute minimums are:
- MSFS Addons Linker (before anything else, so that you can control, categorize and load on demand all items below)
- Bijan seasons mod (although it’s not free and it’s not from flightsim.to, but it’s still #1. Just buy it)
- Global AI Ship Traffic
- We Love VFR (even if you don’t regularly fly VFR)
- Toolbar Pushback
- Enhanced Ground Vehicles
- Yet another ground marks fix
- JP Logistics 152 (separate aircraft than Asobo C152 but a lot better)
- All asset packs (such as Dave’s libraries, AssetPacks etc, as they are dependencies for several freeware airports and/or scenery)
- Go to Microsoft Flight Simulator | Scenery Map » Flightsim.to and search for the departure/destination airports and/or scenery and landmarks around them. I’ve categorized them by country in MSFS Addons Linker and won’t load them all, just whatever I need for each flight. Keeps loading times at a minimum.
And of course other mandatory tools that can’t be found in flightsim, such as LittleNavmap, SimtoolkitPro, Navigraph charts, VATSIM-related apps, spad.next, OnAir Company etc.