Several of the stocks you owned through Swell likely paid dividends to shareholders. Dividends are usually paid quarterly, as of an announced ex-dividend date
If you owned a stock as of the ex-dividend date, then sold the stock and withdrew your funds before the dividend was paid, then the dividend would deposit into your (now) empty Folio account.
This will increase your Folio account balance from a few cents to several dollars, depending on how much you had invested.
If you initiated an account transfer, Folio will forward these funds to your new brokerage account. If you withdrew funds to your linked bank account, you will need to request the remaining balance from Folio.