3rd party software for Windows 1.0
Initially, Windows was not very popular with software developers. Although it was a decent package, many felt it left a lot to be desired in terms of features and performance, while the GUI in general was still a novelty thing. It's no surprise that Windows applications began showing up in greater numbers only after the release of Windows 2.0, when the long-term viability of such an environment became clear.
There were some early adopters, like Micrografx. Over time, several major professional applications were made for Windows 1.0, as well as many freeware and shareware applications created by hobbyists and enthusiasts. To make Windows applications more affordable and accessible to those without a copy of Windows, Microsoft allowed developers to bundle a runtime version of Windows 1.0 with their applications. This practice continued into Windows 2.x, but ended with Windows 3.0 since the overall architecture of the system has changed significantly and no longer favoured this approach, and Windows was much more popular by then anyway.
Despite the fact that some programs were already announced for Windows in 1986 or 1987, by the time they actually shipped, Windows 2.0 was already almost done or already available, so these programs ended up targeting Windows 2.0 instead. Though many such applications will run just fine on Windows 1.0, I've only included those that officially supported Windows 1.0 in at least some capacity in the list below. Often only a short-lived initial release supported Windows 1.0, before the application was adapted for Windows 2.x. This makes many of the applications below very hard to find these days.