I'm posting this as Friendica has just turned 13 - yes, it is one of the oldest Fediverse platforms - considerably older than Mastodon, even!

For those who don't know, Friendica is a platform more similar to Facebook: You can create events, groups, you have a calendar, and you can see your friends' birthdays in it.

Yet, you can also use it as a Reddit alternative. Here's how:

• You can follow Lemmy communities and Kbin magazines just like you would follow any group on the Fediverse. These groups then display in a side pane on the left (hidden behind an arrow if you want to browse it on mobile) allowing you easy access to any group you want.
• You can both like and dislike posts (provided that your server didn't disable dislikes) - these federate as up and downvotes to Lemmy and Kbin posts and comments.
• You can add a title to a post (optionally, you do not have to) - a feature that makes it more compatible with Kbin and Lemmy.
• You can format any text (yes, any, including in your profile) using BBCode - you can do some pretty wild stuff with your text: From basic formatting as in having text in bold, italic or in different sizes, you can also make it so the text is centered, change the color of it or set it to use a certain font (provided that both your and the reader's computers have it installed - not a problem with Comic Sans I guess ( ͡° ͜ʖ ͡°) ). Friendica also uses Markdown, but parses it as BBCode - so if you create a text in MD and you want to edit it later, it will be in BBCode. Not all features work in Lemmy and Kbin, but a lot of these do.
• A feature that Reddit does have and Lemmy does not have yet, is Multireddits. With Friendica, you can group any account - whether it's a group or regular account - in a "circle". When you select one of these circles, you will only see posts from accounts inside it. Say you follow two Technology communities from a different Lemmy instance each, one Friendica group also related, and a dev. You can group them all under a circle and only see these posts.

In addition, here are some other features:

• Friendica is a macroblogging platform - that means that you can create entire articles in just a single post. There's virtually no limit on the number of characters that you have; anything that would fit on Facebook, should fit here as well.
• When you post, you can set various categories for your content. For example, I have an Articles category, where every article goes there. I also have a photography category on my profile for every photo I take. I even have a videos category - every video I share from YouTube, goes there.
• You can post any media, plus any YouTube and Vimeo video inline. That means that you can have a block of text, a few images, then another block of text. There's more freedom for you to express yourself the way you want. Also, as I said, titles are optional. You can just not use them if you do not want to.
• In addition to ActivityPub, Friendica also supports Diaspora* and OStatus protocols, so you can have a broader reach in the Fediverse. There's even initial support for Bluesky, if you have an account already (server-to-server communication is planned).
• There's a plethora of settings that you can play with. You can go wild in customizing your profile with different backgrounds, change the color and even the theme (from a set that your server has installed).
• Servers can also install various addons which add extra functionality. From various protocols (you can even crosspost to Tumblr!) to things like a language filter or collapsing posts if they contain certain words - there's a lot of functionality in them.
• You can hide accounts from your follow list, you can add notes to them, or you can set your account to automatically boost any post made by these accounts - great if you have an alt. I use it to automatically boost my Bookwyrm account posts.
• Friendica is also compatible with RSS - yes, you can have RSS feeds as regular accounts, and have articles displayed in your feed - sometimes as posts, if the website allows parsing the articles. If not, only as links. You can "quote share" these links (yes, Mastodon does not have quote share) and create posts to your favourite Lemmy communities, for example directly.
• You can create community pages, just like on Facebook - and switch between these in the menu. A great thing if you have a business, but you do not want to have separate accounts with separate passwords.
• You can also have notes in your profile, that only you can see. You can also group these under categories as well.

Plus many other features :D

I'm for almost a year already, and I have to say I'm pretty satisfied with it. While I do not recommend it for everyone (it is quite complex), once you get the hang of it, you might find it very versatile for your needs.