I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! 
The Serika 2:
They also did a MT3 version - which I really like as well:
(Photo source: keebtalk, Manufacturer’s site: MT3 Serika – ZAMBUMON)
Timeline
Orders will open on December 3rd, 2020, and will close on January 7th, 2021. Estimated shipping date: Q3 2021 (on or before October 31st, 2021)
Available kits
Hiragana Core - $110 and Latin Core - $110
Basic layout coverage for 60%, 65%, 75%, TKL, 96-key, 1800, and full-size layouts in both standard and winkeyless variants for both ANSI and ISO layouts, all of that while keeping in mind affordability.
The Macro Expansion add-on kit extends the Core’s layout coverage and provides support for 660-like keyboards (2.25U Shift), standalone numpads (double zero and equals key), ergonomic and split keyboards (split space bars and a second B), 88-key tenkeyless boards (F13), 60% keyboards with arrows (2.00U and 1.00U Shift) and extended boards such as the ION Zenith (M1-M10 keys).
The Forties extension kit adds layout support for small form factor and ortholinear keyboards such as the OLKB Planck, ION × AI03 Equinox, or AE × Percebe.
The International extension kit provides layout coverage for Danish, Finnish, German, Norwegian, Swedish, and UK ISO keyboards.
The Geometries accent kit is a small kit with geometric novelties and accent arrow keys.
The Space Bars accent kit includes accent space keys from 1.00C to 7.00C for both standard, split, and 40% keyboards.
RW × Serika Novelty Keycap ($42)
For Serika 2, RAMA Works will be producing a beam finish (polished anodized aluminium) with enamel infill novelty keycap.
Salvun × Serika Novelty Keycaps ($56)
Salvun will be producing two brass novelty keycaps that are cerakoted, then laser etched and finally clear coated. Available in either grey and beige and yellow and black
Pricing and where to buy
Vendor Hiragana Core Latin Core Macro Expansion Forties International Geometries Space Bars RW × Serika Salvun Grey Salvun Yellow Daily Clack AUD $152 AUD $152 AUD $83 AUD $69 AUD $110 AUD $62 AUD $41 AUD $63 AUD $84 AUD $84 Desk Hero CAD $150 CAD $150 CAD $82 CAD $68 CAD $109 CAD $61 CAD $41 CAD $57 CAD $76 CAD $76 ILUMKB SGD $149 SGD $149 SGD $82 SGD $69 SGD $109 SGD $62 SGD $41 SGD $62 SGD $82 SGD $82 Novelkeys_ USD $110 USD $110 USD $60 USD $50 USD $80 USD $45 USD $30 USD $42 USD $56 USD $56 Oblotzky Ind. €115 €115 €55 €47 €72 €39 €25 €42 €52 €52 ZFrontier (CN) RMB ¥828 RMB ¥828 RMB ¥395 RMB ¥330 RMB ¥550 RMB ¥300 RMB ¥200 RMB ¥295 RMB ¥395 RMB ¥395 Zfrontier (Intl.) USD $136* USD $136* USD $65 USD $54 USD $90 USD $49 USD $33 USD $45 USD $60 USD $60
- Shipping included
If I get a Planck, I would need the core kit, the forties kit, and because the geometries kit is so cool, that one too! 
If the colours are going to be the same as the Serika one, I think I might have to justify it as a treat for myself for my next birthday!