These are the best custom ROMs available for the T-Mobile LG G3 smartphone.
Resurrection Remix v5.6.7 ROM:
Resurrection Remix v5.6.7 custom ROM is based on CM 13, which almost resembles Android 6.0 Marshmallow in user interface and features. The developer options are already enabled in this custom ROM and from there you can easily enable the multi-window option and load two apps side by side on the same screen (multi-window feature is in beta mode and apps might get crash that may result in losing any useful data, perform it at your own risk).
Features: Android 6.0.1 Marshmallow based, fix low battery warning level, heads up snooze, reverted clock second, development settings, tune up dexopt dialog, translation imports, force heads up in all notifications, add weather context provider, fix battery stats helper derp, implement left swipe on lock screen, use window attachments, framework changes for resetting data usage stats, update ambientsdk version 1.5.2, mount service, network management, background data access, fix location tile not showing in key guard.
Download: Resurrection Remix v5.6.7 ROM
BlissPOP custom ROM is also based on CyanogenMod 13 with stock UI and features from Android 6.0 Marshmallow. Team Bliss started this custom ROM project when Android 5.0 Lollipop hits the Android smartphones and still working when the sweetest treat Android 6.0 Marshmallow sweetens the smartphones. There are lots of customization options added with a custom kernel to increase the performance of the phone.
Features: Android 6.0 Marshmallow based, CM 13 theme engine, battery icon options, customize-able quick setting tiles, toast and list view animations, memory bar options, status bar header, flash light option, custom color tile options, app circle bar, link ringtone and notification toggle, alarm sound options, brightness level, adaptive brightness, wake on plug, font size, LCD density, show search bar in recents, day dream, sleep time, rotation.
Download: BlissPOP 6.3 ROM
Unofficial Dirty Unicorns 10.0:
Dirty Unicorns 10.0 custom ROM is also based on Android 6.0 Marshmallow with tons of user interface customize-able options. Dirty Unicorn custom ROM is installed with synapse plus app, and DU certified themes app with which you can theme your complete phone perfectly and beautify your phone. And with Synapse+ you can tweak the performance by overclocking the CPU.
Features: Android 6.0 Marshmallow based,
Download: Unofficial Dirty unicorns 10.0 ROM
XOSP v5.4 ROM:
XOSP v5.4 is based on Android 6.0 Marshmallow and themed as Sony Xperia Z5. XOSP is an open source project for all those who want to have Sony Xperia UI on their phones and port it for themselves. Sony Xperia Z5 stock apps are also added in this custom ROM.
Features: Android 6.0 Marshmallow based, stock kernel, theme chooser, Xperia based boot animations, Xperia Z5 sounds, snap camera, viper audio engine, slimdim, nav bar dimensions, hardware keys on/off, status bar logo, viper audio engine, clock widget, Xperia Z5 home, weather app, weather widget, smart connect, audio recorder, hide SuperSU icon on status bar, toast animations, slimseek bar, network traffic indicator on status bar.
Download: XOSP v5.4 ROM
Liquid Dark ROM:
Features: Android 6.0.1 Marshmallow based, RRO layers support, download center, status bar clock customization, nav bar customization, black list, quick pull down list preference, weather display to status bar, list animation views and inter-polar, app circle bar, AOKP custom system animations, live volume steps,advanced reboot, back button app kill, CM lock clock, toast animations, volume key cursor control, clear all recent button.
Download: Liquid Dark ROM
Features: Android 6.0 Marshmallow based, Turbo tweaks, battery bar, expanded desktop, LCD density changer, double tap power button to toggle vibrations, double tap to sleep on lock screen, double tap to sleep on nav bar, double tap to sleep on status bar, lock screen alpha changer, bottom left and right lock screen shortcut changer, middle lock screen shortcut changer, lock screen weather, Google search bar toggle, recent clear all button toggle, immersive recent options, slim recents, slim nav bar customization.
Download: Turbo ROM
PAC MAN ROM V6:
Features: Android 6.0 Marshmallow based, advanced keyboard options, battery bar, slim recents, slim PIE, slim recents, halo, PAC performance, network speed indicator, list view and toast animations, wavelock blockers, PAC console, progress bar customization, quick settings customization, gesture screen unlock, low battery warning, custom tethering network, gesture anywhere, see through lock screen.
Download: PAC MAN ROM v6