I didn't do this as my kitchen extension was 9 years ago but bouncydog beat me to it
All isolator switches in one cupboard.
That means no fused spur switches or your cooker switch being on the walls, you can literally run them all (labelled) into the bottom shelf of a base unit. Put them at the back so you can still use all the space in front.
Another thing I wish I had room for was an appliance shelf in the utility, elbow height for ease of access but the stand mixer, instant pot, slow cooker etc could all live on there rather than in a cupboard like they do now but that truly is first world problems.
And lastly, cutlery bins rather than the drawer inserts, so they are upright instead.
Things I did do and still love
Quooker
Waste disposal unit, mainly so I didn't have to clean the bits that get caught in the plug strainer, the children could tip their left over milk and cereal into the sink too plus toaster crumbs when cleaning the toaster
All my base units are pull out larder units
Tall larder cupboard with internal drawers so I could determine the height of each one
Induction hob with ability to combine zones
My spice drawer is a normal sized drawer but my spices are all laid down, Ikea do a drawer organiser for this purpose.
And lastly, plan all the sockets for appliances, we have ours in neighbouring cupboards with a cut out in the back panel. This means I can turn off and unplug the larder fridge easily before pulling it out, putting it back is done using some string tied around the plug and fed back through the hole meaning you don't have to squeeze between the fridge and cupboards if the lead is short. Same with the washing machine etc.