Keyboards & Input Methods
Most users probably live with the pre-installed keyboard app. Either because they are satisfied with it, that they are not aware of alternatives, or that the alternatives known to them are not really alternatives to them. Only few will know all available keyboard apps (even I don't). But even if the following list is far from being complete, they might prove helpful to the one or other.
Important to consider is that such a keyboard app is aware of all input done with it (well, that's its job, right?). Theoretically it could record all input (including passwords and other sensitive data). In case it also holds the permission to access the network, one could imagine some evil things. So better think twice if there are concerns to consider!
The permission to read/write user dictionaries is fully legit here, however – as that's what keyboards use for spell checking and „predictive typing“.
Keyboards supporting Swipe, Type, and Voice
- Gboard - the Google Keyboard (4.5@18,489,820) Ǥ 31

1 
- Microsoft SwiftKey AI Keyboard (4.4@4,544,113) Ǥ 20

5
Datenschutz-Test 7/2019 - Bobble AI Keyboard Memes, Gifs (4@479,441) Ǥ 27

7

- Smart Keyboard Pro (3.3@22,337; ~EUR 3.50) Ǥ 7

dictionaries available for many languages
Keyboards for Typing
- Keyboard Designer: Keyboard (4.6@1,232) Ǥ 3

Vorstellung 8/2020 - Simple Keyboard (4.4@11,318) 1

Github; Vorstellung 8/2019 | 11/2023 - Hacker's Keyboard (4.3@60,498) 3
LastUpdate: 2018-12-07 Github; Video Review 6/2018; not only for hackers 
- Indic Keyboard (4.3@9,044) 6

GitLab - Unexpected Keyboard (4.3@3,300) 5

Github - OpenBoard (4.3@2,539) 4
LastUpdate: 2022-11-03 Github; Review 6/2021; Vorstellung 11/2023 - Typewise Offline Keyboard (4.3@2,138; ~EUR 25.00) 3

Vorstellung 6/2016 - Big Font - Big Text Size (4.2@37,396) Ǥ 9

3

- Tiny Keyboard (4.2@373) 0

Github - Compass Keyboard (4@56) 3
LastUpdate: 2018-03-16 Github; International keyboard - Simple Keyboard (3.9@7,178) Ǥ 7

9
Github - 1C Big Keyboard (3.7@24,565) Ǥ 9

14

- DroidTR IME (1@89) 2
GitLab - Thumb-Key (0@0; ~EUR 18.00) 1

Github; Kurzvorstellung 8/2023 - K9Keyboard (0@0) 1
LastUpdate: 2023-03-18 Github; T9 keyboard - T16Fling (0@0) 0
LastUpdate: 2021-04-20 GitLab - HeliBoard (0@0) 6
Github; fork of OpenBoard - Fossify Keyboard Beta (0@0) 2

Github
Keyboards for Typing & Swiping
- Kika Keyboard: Custom themes (4.8@390,853) Ǥ 29

12

- Grammarly-AI Writing Assistant (4.1@259,327) Ǥ 8

2

- Multiling (Classic) Keyboard (3.9@44) 5
LastUpdate: 2015-08-26 / Multiling O Keyboard + emoji (3.9@34,766) 4 

- Typewise Custom Keyboard (3.6@14,849) Ǥ 8

Intro 2/2020 - GO Keyboard Lite - Many Theme (3.5@2,528,639) Ǥ 19

13
LastUpdate: 2021-06-01 - Ginger Keyboard - Emoji, GIFs (3.5@183,417) Ǥ 22

11
Video Demo 3/2015; spell and grammar check - AnySoftKeyboard (3.4@26,415) 6

Github; Wiki; MobilSicher Empfehlung 10/2019; Vorstellung 6/2020; Testbericht 10/2023 - Chrooma GIF - Emoji Keyboard (2.8@179,420) Ǥ 19
9
LastUpdate: 2020-06-07 Kurzvorstellung 2/2016; Intro 6/2016 - Urik (0@0) Ǥ 5

Github - FlorisBoard (0@0) 3
/ FlorisBoard Beta (0@0) 3
Github; Review 8/2021 / Github - Kuaizi IME (0@0) 1
Github; Pinyin - CleverKeys (0@0) 3
Github
Alternative Input Ideas
- mazec3 (jp) -Handwriting (5@566; ~EUR 9.00) 5

1
/ mazec3 Handwriting Recognition (2@183; ~EUR 14.00) 5 
1 
- Graffiti Pro for Android (4.5@1,058) 4

LastUpdate: 2023-06-21 Like in the good-old Palm days 
- Selvy PenScript (4@187) 5

1 LastUpdate: 2024-08-22 - EVA Facial Mouse (3.6@25,352) Ǥ 9
5
LastUpdate: 2019-11-21 Github; emulate mouse cursor by eye tracking - Fcitx5 for Android (3@705) 2

Github - Unistroke Keyboard (0@0) 3
Github; Input like Graffiti from PalmOS for Android - Outspoke (0@0) 7
Github; on-device speech-to-text keyboard - Dotterel (0@0) 4
Github; stenographic input - Whisper+ (0@0) 10
Github; voice recognition based on Whisper
More crazy ideas can be found in the category Personal Assistants (Competition to Siri & Google Now).
Remote Keyboards
… can be found in the category Control your Droid from your Computer
Other Keyboards
- FlickBoard (4.9@133) 2

Codeberg - Irregular Expressions Keyboard (4.8@107) 2

LastUpdate: 2024-02-15 Github; write expressive messages in various font styles - Stroke Input Method (筆畫輸入法) (4.4@14) 0

Github; minimalist Chinese keyboard - Brailliac: Braille Keyboard (4.3@188) 2

LastUpdate: 2024-01-22 Github - kboard (4.2@1,605) 4
LastUpdate: 2022-02-09 Github; XDA 2/2019; Intro 2/2019; a keyboard to end conversations - 8vim Keyboard (4.2@16) 2

LastUpdate: 2024-07-01 Github; vim-like keyboard and editor - Trime (4@393) 10
Github; Chinese IME - NovaKey - Keyboard (Beta) (3.5@892) 5
LastUpdate: 2016-06-23 - YidKey KD (0@0) 0
LastUpdate: 2019-01-22 Github; Yiddish keyboard - Privacy Keyboard : Secure text (0@0) 1

LastUpdate: 2023-08-17 Github; Keyboard for secure E2EE communication - Sayboard (0@0) 6
LastUpdate: 2024-09-06 Github; Testbericht 10/2023; free & libre voice input IME („keyboard“) - Sumire Japanese Keyboard Lite F-Droid (0@0) 3
Github - Czech Diacritic Keyboard (0@0) 15
LastUpdate: 2019-06-19 Github - FutharkBoard (0@0) 1
Github - DuressKeyboard (0@0) 6
/ DuressKeyboardLite (0@0) 0
Github; keyboard with Duress capability (type "different" unlock code, and it instead erases your phone) / Github - Fcitx5 Clipboard Filter Plugin (0@0) 1

Github - Jyutping - Cantonese Keyboard (0@0) Ǥ 1

Github - Sithakuru (0@0) 1

LastUpdate: 2023-12-01 Codeberg; Sinhala keyboard
Keyboard Helpers
- More Physical Keyboard Layouts (4.7@1,080) 0

LastUpdate: 2023-08-19 Github - Keyboard Switcher (4.6@1,302) 8

GitLab - 106/109ハードウェアキーボード配列変更 (+親指Ctrl) [日本語配列] (4.6@38) 0
LastUpdate: 2023-08-18 / Caps to Ctrl (4.6@37) 1
LastUpdate: 2023-08-19 Github; Caps to Ctrl (keyboard layout) / Github - Key Mapper GUI Keyboard (4.4@1,589) 5

Github - Guileless Bopomofo Keyboard (4.4@59) 2

Github - Traditional T9 (4.2@663) 8

Github; T9 IME for Android devices with hardware keypad - Hoplite Polytonic Greek Keyboa (3.9@335) 1

Github; extension for polytonic Greek input - External Keyboard Helper Pro (3.6@3,742; ~EUR 1.75) 7

LastUpdate: 2023-04-26 configure your external keyboard - Nabla : Type Math Symbols (3.5@87) 1

Github; easily type math symbols - Inputting Plus: Ctrl + Z/F/C/V (2.8@1,385) Ǥ 6

1
LastUpdate: 2019-01-22 - Full colemak (0@0) 0
LastUpdate: 2020-12-07 Github; keyboard layout with dead keys etc. for physical keyboards - Neo2 External Keyboard (0@0) 0
LastUpdate: 2021-03-24 Github; Neo2-Layout when using a physical keyboard - Keyboard Layout Companion (0@0) 1

Github; visualise and generate images of alternative keyboard layouts
Further Readings:
- Best Keyboard Apps for Android (9/2023)
- 5 best keyboard apps for Android (4/2022)
- 5 Best Private Android Keyboards You Can Trust + 3 Expert Tips (6/2020 - 3/2023)
- Android-Apps ersetzen: Tastatur (2/2020 - 10/2023)
- Video: Tastatur-Apps: Was sie über Sie erfahren und welche App wir empfehlen (10/2019)
- How to Connect a USB Keyboard to Your Android Phone (7/2019 - 9/2023)
- Best keyboard apps for Android (4/2019 - 3/2023)
- The Best Free and Open-Source Android Keyboard Apps (1/2018 - 10/2023)
- Leserfrage: Empfehlenswerte Tastatur-App für Android (12/2017)
- Die besten Android-Tastaturen: Swype, SwiftKey und Co. im Überblick (12/2014 - 5/2021)
- Best keyboard for Android apps (9/2014 - 3/2023)



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