These are TakaraTomy toys (and maybe some significant licensed items) currently known from official sources, scheduled for release in APRIL in Japan (as well as in Asia, as most Japanese Transformers toys are also released through Hasbro Hong Kong).

These monthly lists will be archived on the 2021 Transformers Checklist if you need to refer to these listings later (if anything is found out later, because these monthly lists won't be updated after their month ends).
Some recent listings for reference...
MAR 2021 listing
FEB 2021 listing
JAN 2021 listing
DEC 2020 listing
NOV 2020 listing
AUG-OCT 2020 listing

Dates and details can change at any time - Approximate yen prices listed are just a rough guide to their retail price in Japan.
Links were active at the time they were first added and are only there for reference/proof of details - I do NOT endorse or promote any of those businesses.
(posting corrections or additions are greatly appreciated)

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APRIL 2021

Kingdom Series
- KD-04 - Megatron (Beast) (LDR - same as Hasbro version?) - Late APRIL (7480yen)
- KD-05 - Blackarachnia (DLX - same as Hasbro version?) - Late APRIL (3080yen)
- KD EX-02 - Vertebreak (CORE - same as Hasbro version?) (TakaraTomyMall exclusive) - Late APRIL (1650yen)

Earthrise
- ER EX-20 - Paradron Medix (DLX Ratchet & DLX Lifeline - same as Hasbro version?) (TakaraTomyMall exclusive) - APR 17th (was Late MARCH) (6160yen)
- ER EX-22 - Centurion Drone (DLX w/ accessory pack - same as Hasbro version?) (TakaraTomyMall exclusive) - APR 17th (was Late MARCH) (4950yen)
- ER EX-23 - Decepticon Runabout (DLX - same as Hasbro version?) (TakaraTomyMall exclusive) - Late APRIL (3080yen)
- ER EX-24 - Thrust (VOY - same as Hasbro version?) (TakaraTomyMall exclusive) - Late APRIL (4950yen)

Siege
- SG-EX - Soundblaster (VOY Siege 35th Anniversary - minor redeco Hasbro version) (TakaraTomyMall excl) - MAY 29th (was LATE MARCH) (4950yen)
- SG-EX - Acidstorm, Ionstorm, Novastorm (VOY Siege 3-pack - same as Hasbro version?) (TakaraTomyMall exclusive) - MAY 29th (was LATE MARCH) (14,300yen)

Generations Selects
- Abominus (minor redeco & minor remould - Hungrrr, Sinnertwin, Blot, Cutthroat, Rippersnapper) (TakaraTomyMall exclusive) - APR 17th (was Late MARCH) (22,000yen)

Studio Series
- SS-59 - 1986 Autobot Jazz (DLX - same as Hasbro version?) - Late APRIL (3080yen)
- SS-60 - 1986 Hotrod (VOY - same as Hasbro version?) - Late APRIL (4950yen)
- SS-61 - 1986 Kup (DLX - same as Hasbro version?) - Late APRIL (3080yen)


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CONFIRMED FUTURE ITEMS
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MAY 2021

Kingdom Series
- KD-06 - Autobot Warpath (DLX - same as Hasbro version?) - Late MAY (3080yen)
- KD-07 - Cyclonus (VOY - same as Hasbro version?) - Late MAY (4950yen)
- KD EX-03 - Optimus Prime (CORE - same as Hasbro version?) (TakaraTomyMall exclusive) - Late MAY (1650yen)

Siege
- ER EX-25 - Dominus Criminal Pursuit (DLX Barricade & DLX Punch/Counterpunch - same as Hasbro version?) (TakaraTomyMall exclusive) - Late MAY (was APRIL) (6160yen)

Studio Series
- SS-62 - 1986 Scourge (VOY - same as Hasbro version?) - Late MAY (4950yen)
- SS-63 - 1986 Autobot Blurr (DLX - same as Hasbro version?) - Late MAY (3080yen)
- SS-64 - 1986 Grimlock & Wheelie (LDR - same as Hasbro version?) - Late MAY (7480yen)

Hero-X Book
- Generations 2021 - MAY 13th (3000yen)


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JUNE 2021

Masterpiece
- MP-52 - Starscream v2 (new mould) - Late JUNE (30,800yen)

Kingdom Series
- KD EX-04 - Ractonite (DLX - same as Hasbro version?) (TakaraTomyMall exclusive) - Late JUNE (3080yen)
- KD EX-05 - Huffer (DLX - same as Hasbro version?) (TakaraTomyMall exclusive) - Late JUNE (3080yen)

Earthrise
- ER EX-26 - Exhaust (DLX - same as Hasbro version?) (TakaraTomyMall exclusive) - Late JUNE (3080yen)
- ER EX-27 - Bugbite (DLX - same as Hasbro version?) (TakaraTomyMall exclusive) - Late JUNE (3080yen)

Studio Series
- SS-65 - Mv6 B-127 Bumblebee (DLX - same as Hasbro version?) - Late JUNE (3080yen)

Licensed
- Ultimetal - Destructicon Emperor Megatron (Art Storm) - June (98,000yen)


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JULY 2021

Kingdom Series
- KD-10 - Autobot Inferno (VOY - same as Hasbro version?) - Late JULY (4950yen)
- KD-11 - Ultra Magnus (LDR - same as Hasbro version?) - Late JULY (7480yen)
- KD EX-06 - Megatron (CORE - same as Hasbro version?) (TakaraTomyMall exclusive) - Late JULY (1650yen)
- KD EX-07 - Starscream (CORE - same as Hasbro version?) (TakaraTomyMall exclusive) - Late JULY (1650yen)

Studio Series
- SS-66 - Mv3 Autobot Dino (DLX - same as Hasbro version?) - Late JULY (3080yen)
- SS-67 - Mv6 Starscream (VOY - same as Hasbro version?) - Late JULY (4950yen)


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AUGUST 2021

Kingdom Series
- KD-12 - Rodimus Prime (CMDR - same as Hasbro version?) - Late August (14,300yen)

Studio Series
- SS-68 - Mv2 Bumblebee (DLX - same as Hasbro SS-74 version?) w/ Spike (figurine) - Late August (3080yen)

Others
- Top Gun Maverick (same as Hasbro version - Top Gun crossover) - Late August (5,500yen)


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SEPTEMBER 2021

Masterpiece
- MP-52+ - Thundercracker v2 (redeco MP-52 Starscream) (TakaraTomyMall exclusive) - Late SEPT (27,500yen)

Licensed
- Action Figure - TLK Bumblebee (Three Zero) - SEPT (21,160yen)


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UNKNOWN DATE (at time of posting)

Masterpiece
- MP-?? - Skids (new mould) - date TBA (price TBA)
- MP-?? - Reboost (red redeco Skids w/ new head & scooter) - date TBA (price TBA)
- MP52+ - Skywarp (redeco Starscream) - date TBA (price TBA)
- MP-?? - Raiden (new) TBC - date TBA (price TBA)
- MP-?? - Skyfire (new) TBC - date TBA (price TBA)

Generation Selects (TakaraTomyMall Exclusives?) (cancelled?)
- Micron Legend Convoy/Armada Optimus (new)

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RECENTLY CANCELLED


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