Awesome Ortholinear Keyboards 
15x5
75 keys - enough keys for all of the symbols and the arrow cluster, as well as a full-size numpad. Can also convert to a split layout by placing the numpad (or other keys) in the center.
ID75
(image: https://www.tryorthokeys.com/id75)
- Hot-swappable: Y
- Connection: USB-C
- Additional features
- Bottom-lit LEDs
- Links
- https://idobao.net/products/idobao-id75v1-hot-swappable-mechanical-keyboard-kit
- https://www.tryorthokeys.com/id75
XD75
(image: https://redd.it/ccr3gc)
- Hot-swappable: Y
- Connection: USB-C
- Links
- https://kprepublic.com/collections/xd75
12x5
60 keys - enough keys to cover most of the symbols. The lower and raise layers can be used to deal with missing keys.
Preonic
(image: https://drop.com/buy/preonic-mechanical-keyboard)
- Hot-swappable: Y
- Connection: USB-C
- Additional features
- Speaker
- Bottom-lit LEDs
- Rotary encoder support
- Footprint for DIP switches, power adapter plugs, and Qwiic connectors
- Links
- https://www.tryorthokeys.com/olkb
- https://drop.com/buy/preonic-mechanical-keyboard
JJ50
(image: https://kprepublic.com/collections/jj50-50)
- Hot-swappable: N
- Connection: Micro USB
- Links
- https://kprepublic.com/collections/jj50-50
Nyquist
(image: https://twitter.com/martyschaer/status/960277109406134274)
- Hot-swappable: N
- Connection: USB-C
- Additional features
- Split layout
- The bottom row can be broken off to make it a 40%
- Links
- https://keeb.io/collections/frontpage/products/nyquist-keyboard
Helix
(image: https://github.com/MakotoKurauchi/helix)
- Hot-swappable: Y
- Connection: depends the MCU / TRRS for connecting the half
- Additional features
- Split layout
- Additional 2 keys on each side (30+2 = 32 / total: 64 keys)
- Support OLED screens
- Links
- https://github.com/MakotoKurauchi/helix
12x4
48 keys - 12x5 but minus the number row.
Planck
(image: https://drop.com/buy/planck-mechanical-keyboard)
- Hot-swappable: Y
- Connection: USB-C
- Links
- https://www.tryorthokeys.com/olkb
- https://drop.com/buy/planck-mechanical-keyboard
Planck EZ
(image: https://ergodox-ez.com/pages/planck)
- Hot-swappable: Y
- Connection: USB-C
- Additional features
- 47 keys - limited to only a single 2U space in the center
- Links
- https://www.zsa.io/planck/
- Comparison with Planck: https://ergodox-ez.com/pages/planck-ez-vs-olkb-planck
JJ40
(image: https://kprepublic.com/collections/daisy-40)
- Hot-swappable: N
- Connection: Micro USB
- Links
- https://kprepublic.com/collections/daisy-40
BM40
(image: https://kprepublic.com/products/bm40-rgb-40-hot-swap-custom-mechanical-keyboard-pcb-qmk-underglow-type-c-planck)
- Hot-swappable: Y
- Connection: USB-C
- Additional features
- 47 keys - limited to only a single 2U space in the center
- RGB underglow
- Links
- https://kprepublic.com/products/bm40-rgb-40-hot-swap-custom-mechanical-keyboard-pcb-qmk-underglow-type-c-planck
YMD40
- Hot-swappable: N
- Connection: USB-C
- Links
- https://ymdkey.com/products/ymd40-v2-diy-kit-qmk-type-c-pcb-cnc-case-plate-for-40-mini-cute-mechanical-keyboard-similar-to-planck-layout
Levinson
(image: https://redd.it/kp1a5c)
- Hot-swappable: N
- Connection: depends the MCU
- Additional features
- Split layout
- Links
- https://keeb.io/collections/frontpage/products/nyquist-keyboard
Others
BFO-9000
(image: https://redd.it/8wl1b7)
- Hot-swappable: N
- Connection: depends the MCU
- Additional features
- 108 keys
- PCB can be broken off for 4-6 rows and 7-9 columns
- Links
- https://keeb.io/products/bfo-9000-keyboard-customizable-full-size-split-ortholinear
Awesome Ortholinear Keycaps
Finding a non-blank ortholinear keycap set can be challenging because there aren’t enough 1U modifiers in a small set. The following content will assist you in finding a set that matches yours. This is not meant to be an exhaustive list, but rather a starting point for your ideal set.
Ortholinear Keycaps
Surprisingly there are sets that are made specifically for ortholinear keyboards which will come with enough 1U modifiers and a spacebar for your board.
(image: https://drop.com/buy/drop-matt3o-mt3-susuwatari-custom-keycap-set)
- Most MT3 profile sets will offer ortholinear option.
- Some XDA and DSA set will offers ortholinear option.
Uniform Profile Keycaps
Uniform profile such as XDA and DSA means that all caps will be at the same height which enables us to use the unused caps from other rows in place of the modifiers.
(image: https://drop.com/buy/massdrop-x-mito-canvas-xda-custom-keycap-set)
- DSA and XDA are the most common uniform profile while the KAM and ADA are rarer.
- The same height also means that the alpha caps can be switched across the row. So, there is no addon set required for alternative layout users such as AZERTY, Dvorak, Colemak, etc.
- Feel free to compare the profile height at keycaps.info
Full-Size Keyboard Set
Sets that are made for 108 keys full-size keyboards will surely have a spare for your ortho but with mismatch legends.
Use blanks for modifiers
If your favorite profile or colorway does not come with the above-mentioned options. You can just buy blanks to fill in the current “blank” modifiers.