From base:
Languages: English, Chinese, Polish, Slovak, Czech, Bulgarian, Hungarian, French, Swedish, Russian, Ukrainian, Belarusian, Croatian, Vietnamese, Italian, Greek, Norwegian, Dutch, Spanish, Turkish, Brazilian-Portuguese, Portuguese, Hebrew, Romanian, German, Catalan, Korean, Slovenian, Serbian, Thai, Finnish, Arabic, Persian - Farsi, Japanese, Burmese y Danish
Enabled search gesture (swipe up) on the desktop
3way reboot menu (in dev settings)
MIUI Contacts and Dialer
Dark Mode (Night Mode) for all devices
Removed ads in MIUI system apps
MIUI Dialer and Messages apps
Face Unlock for all devices
Vertical clock widget on lockscreen
Steps counter in Assistant screen
More shortcuts on left lockscreen
Wake up gestures for all devices
AI preloading option in MIUI Lab for all devices
Fullscreen gestures for all devices
Option to auto-expand first notification
Notifications priority settings
More edit options in Gallery app
Enabled MiDrive in File Explorer
Added landscape mode for SMS app
Sunrise/Sunset in the weather app
Google apps support integrated
Removed 5GHz region restrictions
Confirm dials from call logs
Morning report on alarm at morning
More apps supported for AOD notifications
More styles for AOD screen
Raise to wake gesture
AOD notification received animation
Default volume control stream toggle
Tap fingerprint sensor to wake toggle
More Camera features
Double tap to lock screen
Battery AI scenes
Allowed disabling specific system apps
Importing theme .mtz from via ThemeManager
No useless Chinese bloatware apps
More free RAM due to less background processes
Unified flat style app icons for both system and 3rd party apps
Advanced menu with color icons
No any Chinese character under the full system Mi Video, Mi Music, Mi Browser: No any useless Chinese content
No possibility to re-lock bootloader accidentally
Added T9 dialer support
Added charging sound switch
Added Screen-OFF animation
Optimized GPS settings
Optimized Battery consumption
Optimized RAM consumption
Added GSMalphabet into SMS app options
Added more icons grid layout 4x5, 4x6, 4x7, 5x5, 5x6, 5x7 (depends on device)
SafetyNet passed (Google Pay)
Play Store Certified
Added automated tasks in Security app
Added game speed booster
Added erase module (magic elimination) to Gallery photo edit options
Fixed low volume sound via headphone
Charging screen for all devices
Widevine L1 (for supported devices)
From ONE Team:
OTA Updates Weekly's
Unique Xiaomi AirDots App (Download It from OneOS Space)
Corrected icons of third-party apps
Added the ability to hide blocked numbers from contacts in call log
4 volume bars instead of the typical 3
User interface of Chinese developer settings
Removed Xiaomi telemetry applications
Removed non-essential Xiaomi applications that do not affect your cloud
Climate of Samsung (Port) instead of Xiaomi
Unlocked options only available in the weekly China camera (MiMoji does not work until a space error is corrected)
Fixed wrong Russian and Spanish language strings
Extended reset menu, similar to the real Xiaomi interface
Ability to disable any application (even settings, although obviously strongly discouraged)
iOS emoticons
APN configuration more updated than that of Official Xiaomi
Own store of updated system applications
Improved International GPS
More things that I don't remember right now