Time is ticking for me to max out my ISA allowance before the current tax year slams shut. So I’m searching for the best FTSE 100 stocks to buy to make full use of my Stocks and Shares ISA.

Any of the £20k allowance I don’t use can’t be extended into the 2025/26. Of course, I don’t actually need to buy any securities to make use of it. Rather, I just need to have the money deposited in my Stocks and Shares ISA to shelter myself from capital gains tax and dividend tax.

But the exceptional value on offer from many Footsie shares means there’s no point in my delaying. With this in mind, here are just a couple of blue-chip stocks on my watchlist today.

Fresnillo

Soaring precious metals have powered Fresnillo‘s (LSE:FRES) share price to two-year highs. Yet at 947.5p per share, the gold and silver producer still offers excellent value on paper.

A forward price-to-earnings (P/E) ratio of 14.9 times isn’t much to get excited about. But its corresponding P/E-to-growth (PEG) ratio is.

With City analysts tipping a 126% earnings jump in 2025, Fresnillo shares deal on a PEG well below the value threshold of 1, at 0.1.

There’s no guarantee that safe-haven demand for precious metals will keep rising. Commodity markets are notoriously volatile, meaning Fresnillo remains at risk of a price reversal.

But as things stand, things are looking good for silver and gold (which last week hit its 17th new record high in sterling terms in 2025 alone).

Concerns over the geopolitical and economic policies of the US Trump administration continue to mount. Fears over government debt, and escalating war in Europe and the Middle East, are also supporting flight-to-safety assets.

Fresnillo’s portfolio of eight operating mines makes it an especially attractive gold stock to me. Unlike smaller operators, it’s able to better absorb localised problems at group level.

Coca-Cola Europacific Partners

Coca-Cola Europacific Partners (LSE:CCEP) has just rolled into the FTSE 100 from the FTSE 250. It joins Coca-Cola HBC, which sells the same range of market-leading drinks (including Coke, Fanta, and Costa Coffee), just in a different part of the world.

As its name implies, the business sells product into European and Asian markets, 31 in all. Its footprint comprises a mix of developed markets (such as the UK, Germany, and Australia) along with emerging regions (including Indonesia and the Philippines).

This gives the company stability as well as exciting sales opportunities in faster-growing territories. It’s a mix that drove sales 11.7% higher over the course of 2024, to €20.4bn.

Like Fresnillo, Coca-Cola Europacific’s forward P/E ratio of 20.6 isn’t especially low on paper. However, a predicted 27% earnings increase this year also leaves it dealing on a rock-bottom PEG multiple of 0.8.

The business has to spend fortunes in marketing to stay ahead in a competitive industry. It’s also vulnerable to adverse exchange rate movements.

But on balance, I think it’s a top stock to consider this ISA season, along with that blue-chip precious metals producer.