Trojan.Agent refers to a generic Trojan malware detection. It is used for detections that are either associated with no specific malware families or not enough information is available to pinpoint the malware family.
Trojan.StolenData is the generic detection for files that find and delete files, folders, and registry entries with user data gathered by other Trojans.
Although the data is usually stored and encrypted on the users’ machines, be aware that these are stolen, and one should act on this knowledge. Change your passwords. Use a password manager if you weren’t using one, so it’s no hassle to use a different and complex password for all accounts. Also be aware of spear phishing attempts, and other attempts to defraud you with the stolen data.
Malwarebytes can remove this trojan without further user interaction. Take note that other malware should be removed along with this Trojan. This is because other malware may be responsible for creating the detected files, folders, and registry entries that are detected as Trojan.StolenData.