Southern District of NYC is investigating Russian ties to Trump's inauguration, along with a Trump SuperPac that Manafort was involved in. Part of the investigation is also into foreign influence into numerous campaign and cabinet members.
DC US Attorney is investigating the NRA and their financial ties to Russia, specifically through Maria Butina, also involved with the Trump campaign.
Then there is a redacted case that is only known about due to a statement regarding Michael Flynn's cooperation with the Feds. Who knows on this one.