Alnwick on Wikipedia.
 

Of Alnwick Abbey (Premonstratensian) nothing remains except for the gatehouse, seen here (distantly) by Streetview in 2017. NU 1786 1407. Link. Grade I listed.

Alnwick Cemetery on South Street has two mortuary chapels, both dating from 1856. The North Chapel (still in use, grade II listed) is marked on early maps as Episcopalian, later CoE, and the South Chapel (also grade II listed) as "Dissenters" and later as Non-conformist. CoE - NU 1957 1226, Nonconformist - NU 1957 1222. Both © Richard Roberts (2018).

Baptist Church on Lisburn Street and Upper Howick Street, as seen by Streetview in 2018. Its grade II listing dates it to circa 1840. NU 1859 1301. Link.

Chapel Lane Methodist Church (founded as Wesleyan, 1786). NU 1856 1319. © Peter Morgan (2009). Grade II listed.

The Christian Brethren Hall on Percy Street. NU 1864 1310. © Alan Craxford. By 2023, this building was in use as a vet's surgery.

Church of Jesus Christ of Latter-day Saints on Linnet Court, as seen by Streetview in 2016. NU 1964 1155.

Hulne Abbey (remains of), about 2 miles N.W. of the town. Now known as Hulne Priory. NU 1637 1572. From an old postcard in Steve Bulman's Collection.

The former St. Mary (R.C., built 1856) now houses the Bailiffgate Museum. NU 1851 1363. © Alan Craxford. Grade II listed.

The remains of St. Mary's Chantry stand at the nothern edge of the town on Walkergate at NU 1847 1379. The Streetview view is poor, but there are good photos on its grade II* listing.

St. Paul (R.C.) on Percy Street. © Bill McKenzie. Another view, © Alan Craxford. Interior view, © Peter Morgan (2009). Peter advises that this was previously the Anglican St. Mary (1847, closed 1978). It was sold to the Catholics, who re-named and re-opened it soon after. Link. Grade II* listed. The gatepiers and gates are also listed, as grade II.

There is a listed building entry (grade II) for the former Sion Meeting House (2009 Streetview) on St. Michael's Lane. It has a plaque dating the building to 1815. Which group Sion belonged to is so far unclear. None of the earlier maps available to me show it as a place of worship, but it is so marked on a map of 1954. NU 1863 1318.  

The 1954 1" O.S. map shows a place of worship on Bondgate Without at NU 1895 1320. Earlier and later maps don't show it as such, and I haven't been able to discover what it was. It stood somewhere behind "Enhance Beauty Rooms" in this 2023 Streetview.