Note: Both “Frozen Roars” and “Blooming Rose” have yet to be fully revealed. Each of them are also forced readings for kanji names:
Frozen Roars: 冷薔薇の抱香, “Enveloping Fragrance of the Cold Rose”. This is also a play on 咆哮 houkou, “roar”, since the “envelop/embrace” kanji is read as hou and the “fragrance/perfume” kanji is read as kou.
Blooming Rose: 漆黒の薔薇の開幕, “Start of the Pitch-Black Rose”.

Most likely, these cards are referencing Aki’s synchro chant for summoning Black Rose Dragon:
冷たい炎が世界の全てを包み込む。漆黒の花よ、開け！
Tsumetai honoo ga sekai no subete wo tsutsumikomu. Shikkoku no hana yo, hirake!
“Cold flames shall envelop the whole world. Pitch-black flower, come into bloom!”

Sources:
Yugioh.jp
VJump YT Channel