A name does not sound strong because a big dog wears it. It sounds strong because of its consonants: a hard stop at the start, a closed ending, few soft vowels in between. That is a property of the spelling, so this site computes it instead of judging it.
What this list is not
It is not a list of names for guard dogs, and there is nothing here about which breed suits which name — the registers record what animals are called, not what anyone concluded from it. If a name on this list belongs on a whippet, that is between you and the whippet.
Strong and short
One syllable and a hard ending is the most carrying combination there is, which is why so many working dogs have names shaped like this.
Every count on this site is a tally of real registrations: pet licences and shelter intakes published as open data by New York, Seattle, Austin, Montgomery County, Cambridge, Zurich, Basel and three Australian councils. Popularity here is the average share a name holds across those registers, so a name common in a small city is not buried by one common in a large one. Nine of the eleven sources are North American, so read the ordering as naming in those places rather than worldwide.