Maybe it's just my bad luck but I haven't been able to find this in a long time so I thought just in case anyone needs it and before it disappears again, VTS has Aluminum Pigmented Gutterseal in the 5 oz tubes for $15.99.
Geocel Instant Gutter Seal Gutter & Narrow Seam Sealant is a single-component, elastomeric, semi-self-leveling, high performance tripolymer sealant designed to prevent the passage of air and moisture through small joints or seams.
OSI GS121 Gutter and Seam Sealant is composed of high quality resins and polymers which cures to form a tough, rubbery seal. This seal expands and contracts with the change of weather and temperature without cracking. Formulated especially for sealing aluminum, galvanized and vinyl clad gutters and downspouts.
Both can be smoothed and cleaned up with paint thinner. I dip my finger in paint thinner to clean it when smoothing over divots and flaws. Your finger will get sticky if not cleaned as you go.
These are not butyl. The butyl caulks like Dicor are more for sealing around roof vents, protrusions and other non-permanent items. Butyl can be removed for repairs. It's not fun but can be done. It also will crack with time and needs to be touched up. It sticks to itself if the old sealant is cleaned. Butyl caulks are never used to seal old cracked putty or seals; it just won't work.