Older white LEDs (ca. 2005-2010?) had a distinct purple tinge while modern ones have a spectrum much closer to a blackbody. I rather like the look of the older style and would like to purchase some now. Does anyone know what keywords to use to find the older style in a parametric search?
These are called "Full Conversion White LEDs" though by the early two thousands they were partial conversion so you want to look for "Partial Conversion White LEDs". They worked by producing a UV light that excited a phosphorus layer that produced the white light. Some of the purple light from the UV would seep through and cause a purple tint. Also try looking up "Phosphor Film Conversion LED".
Here is an article that talks about them and their history: https://hackaday.com/2018/10/29/history-of-white-leds/
Here is a more technical article discussing it: https://www.digikey.com/en/articles/phosphor-film-conversion-for-white-leds
To be more specific the full name would be "Phosphor conversion indium gallium nitride white LED" sometimes called InGaN, the phosphor used is called yttrium aluminum garnet or YAG. Here is a picture of it:
You can buy them here (notice the blue hue in the picture):
Note: The "Cool White" modern LEDs mentioned in the other answer do not have a color spectrum that looks anything like first-gen partial conversion LEDs. Cool white will still come across as white, though towards the blue part of the spectrum. But the InGaN with YAG phosphor will actually look as though it has a distinct bluish color with a strong blue peak in its color spectrum that exceeds that of modern Cool White LED.
Whilst the exact LEDs may not be readily available due to changes in manufacturing, modern white LEDs (and LED light fixtures) will often be called "warm white" for a more yellowy colour which mimics incandescent light or "cool white" which is more blueish like these older LEDs. So if you choose a "cool white" LED, that will give what you're looking for.
To make this more exact, manufacturers will specify a colour temperature. See this link for a more complete illustration of colour temperature and how it affects lighting.