The following UK B-sides were never collected on American LPs or singles, but may be found on CD on The Singles Plus and other such collections, or else you can try to track down the original UK singles:

The Following two songs uniquely appeared on the Canadian Capitol Today album, and have never been (legally) released anywhere else:

The following four tracks were not released until the 1980s and 90s, thus it's hardly fair to fault Laurie for not releasing them:

(All but "Hello Little Girl" were originally released on the 1984 Music For Pleasure collection The Very Best of Gerry and the Pacemakers, which is itself available on LP. "Hello Little Girl" was first dusted off in 1991 for The Definitive Collection, and has to my knowledge only been released on CD. All four songs are collected on the Repertoire CD reissue of Ferry....)

For the four live tracks, one has little choice but to track down the Gerry in California EP, and I wish you luck in doing so!

CDs

EMI seems willing to license the Pacemakers recordings to just about anyone who comes knocking with a proposal for a "Greatest Hits" album on a special markets label. As a result, one very easily grows frustrated trying to figure out exactly what logic (if any) went into the myriad releases on the market.

The original idea seems to have been to follow up The Singles Plus with reissues of the two British albums with bonus tracks to fill the gaps of EP and unreleased-in-Britain material. For whatever reasons, EMI decided not to reissue the albums at first, and licensed them to Repertoire Records of Germany (effectively Europe's answer to Rhino Records). Combining these two CDs with The Singles Plus, one has a very comprehensive collection of Gerry and the Pacemakers recordings, lacking only the following eight tracks:

None of these tracks has, to my knowledge, turned up on any authorised release. It wouldn't surprise me greatly if the source tapes have been misplaced as all of these songs are from the 1966 sessions for the Girl on a Swing/Today North American LPs.

Unfortunately, the logic of this reissue programme has been forgotten. The Singles Plus, with its mid-1980s digital mastering, has long been deleted, and since 1997 EMI has flooded the market with three issues of its own of the UK albums: the mono/stereo issue, the 2on1 issue and the Japanese issue with a different scheme of bonus tracks. The songs unique to North America from 1965 and 1966 have, more or less, fallen off the map on EMI reissues, and the four live tracks have not, to my knowledge, appeared on anything from EMI. There are probably a dozen CD Greatest Hits collections licensed worldwide by EMI (plus a similar number licensed by whoever holds the rights to Gerry's 1980s recordings), with these reissues generally drawing on a pool of about 35 or 40 songs to make similar-but-not-quite-identical track listings.

EMI America seems to have a scheme not entirely devoid of merit for licensing the Laurie masters it now owns to reissue the first two American LPs on a single CD. Unfortunately, only disc one of the above proposed schme has been licensed to Collectibles Records, and it only contains "Girl on a Swing" as a bonus track--completely out of context alongside 1963 and 1964 material! Nevertheless, given that the US albums did a better job of collecting the entire recorded output on LP, I think it would be quite a sound decision to base a comprehensive re-issue programme around these LPs. If we can go into fantasy mode for a moment and suppose there were a carte blanche for designing a reissue series (or boxed set), the following might make quite logical sense and provide a comprehensive and definitive CD series:

Disc One: Don't Let The Sun/Second Album, with "You've Got What I Like" and "Hello Little Girl" as bonus tracks
All output until the summer of 1964.

Disc Two: I'll Be There/Ferry Cross The Mersey, with "It's Just Because" and the Live in California EP as bonus tracks (and perhaps even some more cuts from that concert, if the tapes still exist???)
Roughly summer of 1964 to summer of 1965.

Disc Three: Girl on a Swing, with the following bonus tracks:
Dreams, Fool To Myself, On A Wonderful Day Like Today, Tonight, Walk Hand In Hand, Come Back To Me, Give All Your Love To Me, Hallelujah I Love Her So, When Oh When
Roughly summer 1965 through end of 1966, though the recording dates of the last four songs is still somewhat unclear and one or two might have to be reassigned to another disc.

Disc Four: While we're on this fantasy trip, let's suggest that the tracks from Gerry Marsden's 11 UK solo singles (which are virtually impossible to find in any condition) be reissued officially. Licensing might be a bit complex, given the number of labels involved, but I'm not sure that costs would be too high, given the limited marketability of the properties. If the above three CDs were to be part of a boxed set, I think that many of the die-hard fans (who, let's face it, are the ones at whom such a product would be directed) would welcome the availability of these songs, which didn't even have the opportunity to sail across the bottom of any charts. With only about 22 tracks, the remaining time could be fluffed out with interviews (either vintage or present-day) or other unreleased tracks to fill up the 78 minutes of a CD.

There'd probably be enough space on discs one and three to add some unreleased material, as there must be old acetate discs and demo recordings floating around out there, and television soundtracks (e.g. Sullivan show) are already well-known. (The alternative to an official re-release, of course, is to wait a decade or so until the copyrights on the recordings start to lapse in some jurisdictions, and hope some enterprising re-issue labels in those countries will fill the void.)

1981-1982