The first flag shown is the double-headed eagle from the Coat of Arms of the Russian Empire imposed on the Empire's black/yellow/white tricolour. The flag also includes the motto "Мы - русские / С нами Бог", - roughly "We are Russian / God is with us".

Image from RusAtribut
The second flag is another unofficial one, it appears to be an alteration of the old flag of the Russian Naval Infantry, which was changed in 2020. The flag's emblem has been replaced with a skull wearing the Naval Infantry beret imposed on two crossed anchors, with the motto "Где мы - там победа" - "Where we are, there is victory". The text on the top is "Морская пехота", Russian for Naval Infantry.

Image from RusAtribut
The third, fourth and fifth flags are all the same - the ensign of the Russian Navy, and you've already identified the final flag as the flag of the Russian Federation.