Your 2006 90x64mm card I suspect is from the following:
2006 Pokémon Ramune Sticker AG
2006 ポケモン ステッカー ラムネ AG
Manufacturer: Ensky (エンスカイ)
A matching Absol sticker is listed on this website , and calls it a Ramune Sticker.
It states that you use the top four moves to battle a different sticker.
It seems that there are holographic variants too (see the Chatot sticker).
Of note is that this set includes Generation IV Pokémon, despite having the Advanced Generation label.
Chatot sticker:
As a last side-note, the back art and general artstyle of this card strongly resembles the sticker Seviper No. 831 from Ensky ADV Retsuden the Strongest Seal Part 9. This meant that this card was likely produced by Ensky, which was one of my useful leads.
I was unable to find more information on the Generation III version of these stickers.
However, there are a few more very similar sets that provide more clarity on this type of sticker.
(Unknown Year) Pokémon Diamond and Pearl Ramune Sticker
ポケモン ステッカー ラムネ - ダイヤモンド&パール
Card images:
Pack images:
Box images:
- Source: メルカリ
I was unable to find a year on these, but the expiration date on the pack visible states April 19th, 2008.
Here, you can see the stickers battling each other on the box art.
(Unknown Year) Pokémon Diamond and Pearl Ramune Sticker - Neo Series
ポケモン ステッカー ラムネ - ダイヤモンド&パール - ネオ
Card images:
Neo 3 Pack image:
Neo 7 Pack image:
- Source: Amazon.co.jp
Of note is on the top left, the Japanese logo for the movie Pokémon: Arceus and the Jewel of Life can be seen.
You can see the stickers battling each other on the pack art here as well.