tl;dr
Should I push my fledglings out of the nest myself?
No. You should find like-minded people who are invested in your applications to help you nurture and support them throughout their entire lifetime :-)
Long Answer
If no-one knows your applications exist, you might want to ask yourself why do they even exist in the first place? :-).
Making a software product successful (even in internal one) isn't just about writing code that works - when you get an idea for a new tool you should maybe have a discussion with the owners of the relevant business area or process it's aimed at improving and find a user champion amongst the target staff base before you spend any time writing it.
You can talk to them about what benefits the application might offer (e.g. improved productivity, new business capabilities, better governance, etc), and they might be able to make suggestions on how to refine or improve it.
Or better yet, solicit ideas from your user base about what applications would provide the most value for time and effort spent writing them - they might even suggest a completely different tool that has more value to them right now. They'll also have the relevant business contacts and subject matter knowledge, and will be able to suggest the best way to connect with the target users and organise training.
In short, instead of flying solo in a vacuum, try to build small informal working groups or project teams for each application who are invested in making it a success. You might still be the only developer on the project, but if you can recruit other stakeholders from your audience you'll possibly find they get visibility and adoption a lot quicker.
You might need to get your boss on-side with this first, but if they see it helps you make tools that are more valuable to the business and raises the profile of their team as a side-effect you should be able to get them on board pretty easily.
Personal experience
A long time ago I was a solo developer embedded in the Marketing Department of an international investment bank, responsible for development of a set of add-ins for the Microsoft Office suite that provided interactive corporate branding and page layout tools for internal documents and client pitch books.
Although I did pretty much all the technical work, that was only a small part of the project - over time we built up a large network of international stakeholders who informally helped us outside their regular duties, including regional desktop support teams to deploy the system and troubleshoot end-user issues, trainers to produce manuals and training sessions (including one presented to all new global starters as part of HR induction), and a team of trusted early-adopting users who did testing and gave feedback on updates before we released them, as well as creatives / brand designers, and product enthusiasts / evangelists at multiple levels of the corporate hierarchy from analysts and secretaries all the way up to endorsement from C-level board members.
It was effectively an informal "shadow" startup (think SkunkWorks) within the main organisation - it was totally a team effort, but we were able to get recognition for our work within the company well beyond our official status and the system ended up being installed as part of the standard build for about 10,000 corporate workstations worldwide as a result and used by hundreds of people every day.
If you compare that to what would have probably happened if I'd just uploaded the add-in to the corporate intranet and sent out an email, you can see that perhaps you shouldn't just "push your fledglings out of the nest yourself" - you should find like-minded people who are invested in your applications to help you nurture and support them throughout their entire lifetime:-).