Some links that may be of use.......

From July 2018 Google Chrome warns (in the address bar) that http sites are non-secure and will only give a secure rating to https sites. We have therefore removed all active http links

However many http sites remain extremely useful and we continue to display the description and web address of those sites

General

Antiquers Forum: The forum members have a lifetime of antiques expertise covering a wide range of subjects. There is a strong US presence, but Antiquers also has members from all over the world giving global expertise. We have found them invaluable for insight and identification of items with the added bonus of a strong sense of support and community. Well worth registration for full functionality
https://www.antiquers.com

Glass

20th Century Glass Encyclopedia Comprehensive guide to modern glass https://www.20thcenturyglass.com/glass_encyclopedia_home.htm

Great Glass Useful guide to identifying some makers marks
http://www.great-glass.co.uk/glass%20notes/marka-c.htm

The Paperweight People:
http://www.pwts.co.uk/index.shtml=http://www.pwts.co.uk/index.html

Image Search

Conducting a reverse image search can be a good way of identifying an obscure object or painting/print. Each work by uploading an image from your computer and the search engine then tries to find relevant matches.

Tineye: Our preferred engine as it seems to identify only relevant matches
https://www.tineye.com/

Google: We have found this less useful as it appears to find several non-relevant matches
https://www.google.com/imghp

Patent Searches:

Espacenet
https://worldwide.espacenet.com/

US Patent Office
https://www.uspto.gov/patents-application-process/search-patents

Postcards

Playle Deltiology: US orientated
https://www.playle.com/realphoto/

Edinphoto: Scottish orientated
http://www.edinphoto.org.uk=http://www.edinphoto.org.uk

Pottery, Porcelain and China:

Gotheborg: Excellent site for Chinese and Japanese ceramics. Front end is free but annual subscription required for full functionality http://gotheborg.com/=http://gotheborg.com/

The Potteries: Superb reference site for Staffordshire pottery.
http://www.thepotteries.org=http://www.thepotteries.org

20th Century Forum: A good site for getting other members feedback on unidentified pottery (and glass)
https://www.20thcenturyforum.com/

Nicholnack: Australian site specialising in Royal Doulton and Carlton Ware
http://www.nicholnack.com.au=http://www.nicholnack.com.au

Replacements: An American site that has a extensive index of patterns
https://www.replacements.com/

Studio pottery:
http://www.studiopottery.com/=http://www.studiopottery.com/

Antique Marks: Wide ranging site for antique marks on pottery and more
http://www.antique-marks.com/=http://www.antique-marks.com/

Silver

925-1000:
http://www.925-1000.com/=http://www.925-1000.com/

Silver Collection:
http://www.silvercollection.it=http://www.silvercollection.it

Birmingham Assay Office:
https://theassayoffice.co.uk/

Silvermakers marks:
http://www.silvermakersmarks.co.uk/=http://www.silvermakersmarks.co.uk/

Toys

Vectis Good site for buying collectable toys and checking values
https://www.vectis.co.uk/

Valuation

Millers Antiques:
https://www.millersantiquesguide.com/

Ebay: Ebay remains the main online auction site for the moment although it appears to be moving to more of a mall for online major outlets. However it has millions of items for sale including a huge quantity of collectables. Searching completed listings can provide useful price comparisons with the caveats that condition may vary, sellers may classify items incorrectly and national markets may vary tremendously and it can be dangerous to apply USA values to the UK market and vice versa.
https://www.ebay.co.uk