OSF Preregistration
When researching open science, sooner or later you will stumble upon a website called Open Science Framework (OSF). OSF is a platform that ties together a bunch of open science functionalities. Researchers can create projects with different components, such as an open lab notebook, data, code, and so on. You can do a preregistration of your study here (more on that in the chapter Preregistration), upload preprints, and upload your data (with unlimited space!).
You can use all these functions directly as part of the website. However, what makes OSF so useful is that it offers integration to a large number of other platforms. For example, if you use Github to upload your code, you can directly tie it into your project. If you upload apreprint on bioRxiv, it also gets listed on OSF, and you have the option to connect it to the project it belongs to. OSF also offers integration of referencing software such as Zotero, so that it automatically synchronizes your bibliography as the project progresses. You can also create a Wiki for your project. If you want to upload a poster you can use Figshare to upload the pdfs and integrate them too. Even if you are not interested in all the functions OSF has to offer, it might still be worth it to list your project on the platform. Due to its integration of various other tools, it can serve as a connection point to your data, source code and so on, making your research more discoverable.
Also there are multiple templates for OSF preregistrations available. Make you of them! For fMRI data you can use the following OSF template.