Interface Essential

Business

Images Photography

Money Shopping

Programming

Computer Devices

Phone

Mail

Map Travel

Food Drink

Nature Ecology

Entertainment

Shipping

Culture

Health

Work Education

Artificial Intelligence

Arrows

Streamline 3.0

Ultimate

Core

Flex

Sharp

Plump

Micro

Freehand

Streamline Material

Nova

Cyber

Streamline Vault

Logos

Pixel

Google Material

Tabler

Remix

Feather

Iconoir

Carbon

Solar

Lucide

Brand Logos

Bootstrap

Atlas

Unicons

Ionic Icons

Phosphor

MingCute

Font Awesome

Majesticons

Mynaui

Radix

Heroicons

Flagpack

Block – Free

Platinum

Health Wellness

Plump Remix

Health Metrics

Medical Monitoring

Sharp Gradient

Core Pop

Plump Gradient

Core Remix

Outlined Line - Streamline Material

Activities

Sharp Line - Streamline Material

Health Appointments

Social

Pixel - Free

Health Injection

Health Beauty

Flex Neon - Free

Health Care 2

Sharp Pop

Medical

Core Flat

Flex Pop

Flex Remix

Core Line

Plump Duo

Sharp Flat

Freehand Duotone

Mental Health Heart Time 4

Mental Health

Mental Health Heart Time 2

Health Health Dead

Rounded Line - Streamline Material

Health Activity Deep Sleep

Health Activities

Ultimate Duotone

Diet Health

Dietetics

iOS 14

Ios Health 2

iOS icons

Sharp Gradient- Free

Health Brain 1

Core Gradient

Plump Pop

Plump Neon

Core Neon

Sharp Remix

Flex Flat

Plump Solid

Flex Solid

Core Duo

Sharp Solid

Sharp Line

Sharp Duo

Guidance – Free

Health Services

Cyber Duotone

Businesss Health

Users

Health Bandage

Micro Line

Core Solid

Mental Health Heart Time 1

Core Gradient - Free

Flex Remix - Free

Flex Line

<p>Flex is all about the curves. Its smooth curves brings fluidity and dynamism to your designs with a modern appeal.&nbsp;The Flat style is easy to integrate into projects that need icons with a more illustrative purpose, working best at larger sizes. All Flex Flat icons are designed on a 14px grid with two customizable colors.</p>

**Summary**: Flex's illustrative sub-style — solid flat two-tone blue fills on fluid organic silhouettes, producing a more contemporary and natural-feeling flat illustration register than geometric flat sets. Fluid organic edges soften the flat fill quality, making this register warmer and more natural than Sharp Flat or Core Flat at equivalent blue tonal palette. The tone signals organic illustration: "we illustrate nature's geometry." Best for onboarding and product tour illustrations at display sizes, feature explainer content in modern consumer products, and marketing where organic silhouettes feel more contemporary than geometric flat alternatives.

**Last updated**: 2026-04-23

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## Fit & Recommendation

### Primary use cases

- Onboarding and product tour illustrations at display sizes
- Feature explainer and help content visuals
- Modern consumer product marketing where organic silhouettes feel more contemporary than geometric flats

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## Brand & Cultural Identity

### What it communicates

> "We illustrate nature's geometry."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | None |
| Fill | Solid flat fills, two-tone |
| Corner treatment | Fluid organic silhouettes |
| Color | Dark blue + light blue tonal |

### Emotional Scores

Flex Flat is somewhat warm — the blue tonal system is cool, but organic silhouettes add warmth that geometric flat sets lack. It is one of the friendlier sub-styles in the catalog — flat fills on organic silhouettes produce flowing shape edges that soften the fill. It is one of the friendlier sub-styles in the catalog — the two-tone blue in organic shapes reads as modern and considered, with mild approachability. It is somewhat warm on playfulness — organic flat illustration reads as contemporary and considered rather than playful or severe. On its human↔mechanical character, it is one of the more human-feeling sub-styles in the catalog — fluid organic silhouettes read as natural forms, not diagrams.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Outfit — modern humanist, appropriate for the illustrative flat icon context
- **Alternative**: Plus Jakarta Sans — warm humanist, works in illustrative contexts
- **Body**: Inter Regular or DM Sans
- **Avoid**: Cold geometric or monospace fonts


<p>Flex is a fluid icon family inspired by nature’s curves. It favors smooth, flowing forms. More organic than Core and subtler than the chunky Plump. Read about the <a href="https://blog.streamlinehq.com/flex/" rel="noopener noreferrer" target="_blank">design process</a>.</p>

Fluid icons

Heart Rate Relax

Heart Rate Relax icon - Flex Flat Set

Download Heart Rate Relax SVG vector or transparent PNG icon in Flat style(s) for Sketch and Figma. It belongs to Flex Flat vectors SVG collection.