Planned

Titles

Button to go to first chapter or next unread chapter on title page
Bookmark progress to jump to left-off point instead of next unread chapter
Collapse alt titles when lots of titles present
Categorize alt-titles by language/type
Indicate preferred title from alt-titles
Add 'DJ' icon and remove (Doujinshi) from titles
Automatically add manga to follows when rated
External URL fields on Title creation page
Kitsu/AniList links on titles
Set preferred cover to (first/last/reading)
Improve missing chapters tab behavior
Multi-language description support
Hentai tags
Reviews
Additional official link fields

Chapter Listing

Compact View Mode
Hide language flag when one language set
Tachiyomi views increase view count for chapters
Last updated timestamp to respect language filters

Read Markers

Mass marking of chapter read markers
Mark as read (for manga not followed)
Local marking for guests and users
Backup markers on server for users

Search

Sort by Manga ID
View Newly Added Titles
Arabic Search Language Filter
Auto-redirect to manga on one search result
ElasticSearch rework (reopen search for guests)
Post-rework: Search by tags/author/description in quick search
Search within ranges (score of 7 to 8)
Exclude followed manga

Groups

MangaUpdates links on group pages
Custom set delay for uploads
Modify/remove delay on delayed uploads
Invite requests (no more kidnapping)
Graph of views on uploads over time period

Front page

Latest Posts preview character limit
Position carousels under latest forum posts
Custom user arrangement of the front page
Live update of chapter uploads

Settings

BBCode buttons in user biography textbox
Add file size limit to upload boxes
Improve error message when file size above limit
Blacklist groups to hide groups from view
Notifications for new comments on uploads
Rearrange group order on user page
Automated email change
Blacklist language of origin and demographic

Follows

Sort by unread chapters
User-written custom notes
Customized categories (naming and functionality)
Mass-change status of manga
MAL/Kitsu/AniList Follow Imports
Add thumbnails on chapter view
Export follows
Hide series set to dropped
Show: Delayed Chapters

MDList

Sort by user rating
Sort by shared follows/unshared follows with another user
Filter by demographics

Private Messaging

Signatures on PM
Email notification on PM
Select all messages (Delete)
Only receive PMs from friends/group members

Forums

Comment incentive (likes? reactions?)
Live update of comments
Reply button (lol)
New post indicator
Post-preview button before submit
Subscribe to threads for notifications
Forum rework
Custom emotes for supporters
Pinned message in threads
Search

Miscellaneous

Add page jump button to pagination choices
Anonymous upload option
Additional graphs for total site activity stats
Full UI translation for the entire site
Featured titles previous anime seasons
Drag/drop zips onto upload page
Artist/Author pages
Franchise pages for series
Low resolution image server for users with slow internet
Add to follows from inside the reader
Comments while inside the reader
Sync read markers with progress tracker
Delete accounts
User comment history (private/public)
API Rework
Recommend similar series (in-reader and out-of-reader)
Bocchi-sensei (or other help page) in the UI

Rejected

Titles

Collapse related series when lots of entries present (covered by planned Franchise pages)
Total chapter count (per language)
Total page count (per language)
END status (per language)
Character specific tags

Chapter Listing

Notifications/indicator of updated previous chapter

Groups

Edit group name

Front page

Settings

Follows

MDList

Private Messaging

Forums

Disqus
Delete Comments

Miscellaneous

Mass uploading
Features roadmap
Tsukkomi

Reserved post