Software for Windows 1.x and 2.x was always pretty difficult to find. I don't think much exists for them, particularly 1.x. I think there have been discussions on vcfed that go into this in detail.

Two programs I know of for 2.x include Aldus Pagemaker and an early version of MS Office.

win31.de comes to mind. It offers some old program versions for download.

win3x.org has many win3x (and 9x) softwares available too

I wish there was a site dedicated to windows 1, 2 and 3.0 software. There was tonnes of software made for 3.0, but these days it's rather to determine which of the 3.x titles will actually run on it. IT would also be nice to have a list of software that runs in real mode (basically nothing), standard mode and 386 mode. From what I understand the vast majority of 3.x stuff will run in standard mode.

Search gui gallery page. There's some Win1.x/2.x software located.
Also have a look at Youtube, Windows 1.0 is quite popular there ("first Windowz evvaarr").

Personally, I also recorded a few clips about such relics (shameful self-advertising, I know 😊).
On old server (mirrors of them), you may find some public domain and shareware programs for Win 1.x.

Here's one of my oldest Win16 PD programs that I found..

The Game of Life for Windows 1.x, dated 1986.
(Same year as the Norton Commander saw the light of life!)

archive.org has some collections for windows 3.1x and DOS and you might find some win 1.x/2.x stuff on there if you dig deep enough.
- https://archive.org/details/softwarelibrary_win3 Windows 3.1x Main category
- https://archive.org/details/softwarelibrary_win3_games Windows 3.1x Games
- https://archive.org/details/softwarelibrary_win3 Software misc.

That site is really great, but I'd recommend to also check old Shareware discs, ca. '92 and before.
Windows 3.0 was the natural enemy of Windows 1.x/2.x software, because it did set a trend:

Soon after Windows 3.0 became popular, a "porting to Windows 3.0" graze started like a wildfire.
Instead of doing minor modifications to add Win 3.0 compatibility to existing programs,
programmers went the radical way and recompiled their Windows 2.0 programs against the Windows 3.0 API, destroying Windows 1.x/2.x compatibility in the process.
Looking backwards, it is understandable. They simply had no emotional bonds to Windows 1/2. These old GUIs were just tools to them (no nostalgia).
And after Windows 3.0 programs flooded the market, the older binaries on the net and physical media simply got replaced.
IMHO, only choices to get hold of early Win16 stuff are old backups from the 1980s, old computers w/ HDDs from the attic, book diskettes, old server mirrors etc.

The main reason for recompiling apparently was to get rid of the compatibility warning that Windows 3.0 displayed for older apps that weren't "Win 3.0 aware":
Without some bits set in the NE header, Windows 3.x would panicly display a big dialog box, giving the user the choice of abborting or continuing.
That same check is also used by Win 9x, by the way. With the difference, that 9x doesn't allow a choice anymore.

If you modify Win 2.x programs with Mark30 or Borland Resource Editor, Windows 9x suddenly can execute Win 2.x programs.
I wrote some points down in the description in one of my videos: https://youtu.be/uNwk3a8ZxE4

In short these things were important: Win 3.0 awareness, no segment arithmetics - "clean" programming; scalable font handling.
So yeah, Windows 3.0 wasn't the cure. It was the poison. 😉

Edit: The only positive thing about Windows 3.0 was its comprehensive Expanded Memory (EMS) support in Real-Mode, IMHO.
It allowed "flawed" Win16 applications from the 1980s to run in its native habitat, Real-Mode, but with enough memory to actually run well.
Well-behaved Win16 programs for Win 1.x/2.x could also still run in Standard and Enhanced Mode of Windows 3.1x, making Win 3.0 completely superfluous.

Edit: Another thing notable about Windows 3.0's Real-Mode kernal:
It could work together with older drivers written for Windows 2.x and Windows 2.x/286 (but perhaps not not /386).
Once an old Windows display driver is used, the Windows 2.x graphics palette is intact, so Win 1/2 programs using colour do look correctly.
Perhaps you never noticed before, but Windows 3.x has a different palette by default. Just try some older picture viewers.
By comparison, Windows 2.x treated 256 colour devices as high-fidelity displays.

Edit: Just one thing more. Windows 1.x and 2.x weren't very popular originally, but Windows/386 became quite popular.
It was mentioned regulary in shows like the Computer Chronicles, since it could multi-task serious business software for DOS quite well.
So if you're looking for ancient Win16 software, also search for "Windows/386" or "Win386", it may lead to plain Win 1.x/2.x software, too.

Thanks for the directions of the sites.