Earlier today I participated in an OpenAI hackathon and realized a couple of things.
It's now very simple to create a custom GPT, it can be done in about 15 minutes even if you have no coding experience. The hardest part is coaxing the model to create cover art that doesn't have distortions or a shovel with two handles if you are creating a gardening assistant.
There seems to be a decent leap between building a GPT via prompting and adding actions via code which attach to your data. It does look like the mechanisms in place, using OpenAPI specs, to interface with your data have been though out of but it will take some time to create easy dev workflows. This is an area that should be ripe for selling picks and shovels to the giddy AI GoldRush miners. Creating easy to use testing environments for testing out your api changes before they reach a GPT will be necessary as well as a way to test how the GPT will respond as they are non deterministic.
There is no current rankings for GPTs outside of the 8 that are pre selected on the Explore GPT page. You can go in and search for each category that you are interested in but that can be a bit tedious, so I did it for you and now have a list of the top GPTs for over 50 categories. The data includes info about the given GPTs for a category including the number of conversations that have been had with the GPT.
If anyone is interested in the list I have it up on gumroad ready to buy today. Get ahead of the curve with this data as there is no easy way to parse through all the GPT categories currently. As always happy building!