NRICH enriching mathematics offers a set of EYFS resources here:
https://nrich.maths.org/early-years
NCETM has two modules for early years – about counting and number. You do have to register, but it is free. The archives on the site also house past issues of Early Years Magazine with many specialist articles.
https://www.ncetm.org.uk/resources/31856
The Erikson Institute in USA has an early mathematics collaboration website and includes some Big Ideas in mathematics:
http://earlymath.erikson.edu/big-ideas/page/3/
The STEM website includes many links to mathematical materials for the early years
https://www.stem.org.uk/resources/search?=Search&resource_query=Early+Year+mathematics
The Foundation Years site stores several National Strategies publications which still have much relevance, including Numbers and Patterns, Mark Making Matters and Children Thinking Mathematically
http://www.foundationyears.org.uk/wp-content/uploads/2011/10/Numbers_and_Patterns.pdf
http://www.foundationyears.org.uk/wp-content/uploads/2011/10/Mark_Marking_Matters.pdf
http://www.foundationyears.org.uk/wp-content/uploads/national_strategies_resources/childrenthinkingmathematically_psrn.pdf
The National Numeracy Family Maths Toolkit is full of ideas and free activities for children and families:
http://www.familymathstoolkit.org.uk/advice-for-families
Find out more about the NDNA Maths Champions Programme (which includes online audit tools, online training, resource bank with over 700 resources including over 350 activity ideas to support maths through play with materials already in your setting) here:
http://www.ndna.org.uk/childcare-training-maths-champions
This material from New Zealand is intended to support practitioners to use opportunities that arise in everyday interactions with children to foster the development of mathematical thinking:
http://nzmaths.co.nz/supporting-rich-mathematical-interactions-ece
The National Children's Bureau (NCB) website includes the 2014 report Making Maths REAL – Working with parents to support children's early mathematical development:
https://www.ncb.org.uk/sites/default/files/field/attachment/NO20%20-%20ncb_making_maths_real_august_2014.pdf
The Children's Mathematics Network has many examples of children's mathematical mark making and also the taxonomy of children's mathematical graphics
http://www.childrens-mathematics.net/