Looking for cold email advice.

I think using your default email client is fine for cold emails.
I did it for over a year, it allowed me to focus heavily on what I was saying to each person/studio and helped me understand what to say in future emails (e.g. the benefits I could provide etc).

You can try www.mailshake.com it is a simple outreach tool and comes with cool tested templates which you can use for your email campaign. It is a powerful tool which allows you to manage contacts, design campaigns and set automated follow-ups

I use mailshake.com and very happy with it

I strongly recommend streak: https://www.streak.com/

It is a nice Gmail plugin that basically embeds a CRM in your Gmail. And it is free for your use-case.

While UI can be a bit clunky you can do a lot and organize all your leads nicely into pipelines.

Another solution I love is https://reply.io/. It allows for creating campaigns, managing contact lists, A/B testing, validating email address...
Unfortunately, all those features have a cost.

I recently developed one called MailCold at mailcold.com, give it a try :)

Check out gmelius.com.

It works natively from Gmail, so there is no need to learn another tool or switch back and forth.

Along with email templates you can create sequences. Using sequences you can build personalized email flows (smart drip campaigns) based on your recipients' interactions (e.g. if (not)read/replied).

Also, from sequences you can bring specific conversations (contacts) to boards (a fully customizable pipeline management solution) where you can organize columns in a preferred way.

Mixmax gets my vote as a gmail productivity plugin. You can build & test templates, saved me a heap of time.

I recently started using emailoctopus. It's simple and gets the job done. It's not only for cold emails by the way.

I used woodpecker.co and advice from Steli Efti at close.io for a while, my response rate was consistently good. It's worth a try at least to have a look at Steli's blog articles, videos and webinars. The woodpecker.co blog is also pretty good for guidance when it comes to scalability, to avoid any issues when sending a lot of emails.

I think Gmail can work just fine if you are just starting out and need to figure out what works and what doesn't work.

What phase are you in (just starting, or looking to optimise)?