This is the 17244th most frequent Russian word.
сувенирные
"Souvenir" or "related to souvenirs."
Here, 'сувенирные' qualifies the noun 'открытки' (postcards), meaning that the postcards have the characteristic of being souvenirs.
Я купил сувенирные открытки во время нашей поездки.
I bought souvenir postcards during our trip.
In this sentence, 'сувенирные' modifies 'изделий' (items), indicating that the items are related to or intended as souvenirs.
Магазин предлагает широкий выбор сувенирных изделий.
The store offers a wide selection of souvenir items.
'Сувенирные' here describes 'кружки' (mugs), pointing out that the mugs are categorized as souvenir items.